Aluminium rails do not need machined surfaces

Rexroth has developed a linear bearing technology which, it claims, plugs a gap in terms of performance and cost between bushings and ball rails. The new eLine ball rails combine an aluminium base material with raceways made from a hardened, anti-friction bearing steel.

The result, says Rexroth, is a light, compact and corrosion-resistant linear motion technology with an identical loading capacity in all four main directions of loading. The maintenance-free rails weigh about 60% less than equivalent steel rails.

One attraction of forming the rails from a wrought aluminium alloy is that the mounting surface is less critical than normal. In some applications, the rails can even be mounted on sheet steel or on uneven surfaces which have not been machined.

In addition to light machinery duties, in applications such as handling systems and packaging machinery, Rexroth expects the low-cost rails to find uses in non-industrial applications, such as door and window guides, fitness equipment, furniture and vehicles.

The rails, which enter production in April, will be available in three sizes (15, 20 and 25) and in lengths up to 2m. There will be two runner block designs: one for high-accuracy applications; the other for less demanding applications.