User:Bearing-element/Wire race bearing

Cross section of a wire race bearing with ground inner and outer rings

Wire race bearings are antifriction bearings of special design. The rolling elements run on hardened open race rings inserted into apprpriate notches of the enclosing design and not directly on the surface of the bearing rings. Balls, rollers or even cross rollers are used as rolling elements. Due to the design wire race bearings are commonly socalled 4-point-contact bearings.

The first wire race bearing was invented 1934 by Erich Franke, co-founder of Franke & Heydrich KG in Aalen, Germany (nowadays Franke GmbH). As a young designing engineer of Carl-Zeiss-Werke in Jena, Erich Franke intended to design a very space-saving bearing for an optical device. The aim of his thoughts was a much closer relation between bearing and enclosing design to keep it as compact and as lightweight as possible.

Types

The most common type consist of two open inner and outer rings each. Types using just three rings can be used for special applications to compensate e.g. angular offset. There are types forming an converging angle ball bearing using two rows of balls setup with two race rings each. A special type for mainly radial loads can be setup with just two racerings.

Comparison with standard ball bearings

The space-saving design is the main advantage with the capability of loads and moments from all directions at the same time. Because the rolling elements run on race rings, the enclosing design is not exposed directly to stressings of the rolling process. Thus allows to use alternate materials like aluminium, brass or plastic as housing. Toothings may be added to inner and/or outher bearing rings. Another advantage is, that rotational resistance and preload can be adjusted precisley.

Due to the specific design, wire race bearings have also system inherent disadvantages like increased assembly time, because the race rings must be inserted accuratly into the enclosing design to ensure faultless function.

Field applications

Wire race bearings are often used, if there is only little space for a bearing or the assembly should be of lightweight.

Wire race bearing manufacturers

• Rothe Erde Dortmund
• Franke GmbH