Posted to News on 30th Oct 2009, 17:06
Linear bearings offer high-speed, high-load capability
SKF is launching a new range of modular linear profile rail guides for use in demanding industrial applications. The LLT profile rail guides have been developed to combine high operating speeds with heavy load capacities, while offering excellent rigidity, repeatability and accuracy from a system that can easily be configured to meet the needs of both OEMs and end users.
The modular concept of the LLT profile rail guides gives design and production engineers a wide range of system build options in terms of rail length, carriage size and profile, and for factors such as levels of accuracy, stiffness and preloading. For example, systems can be supplied for loads between 8400N and 128,500N, operating at speeds of up to 3.0m/s, with a choice of six types of carriage and unlimited stroke lengths.
In addition, the LLT system is claimed to be unique in enabling the four ball bearing raceways to be configured either in an O or X arrangement, based on the contact angle of the rolling elements. Both systems provide excellent load bearing, acceleration, deceleration and side load characteristics, with the special X-shaped raceway configuration also offering superior self-aligning properties, combined with the ability to virtually eliminate variations between the rail and carriage, even under preload conditions; for example, lateral deviation between carriage and rail is within +/-10microns. This makes the guides suitable for use in high-performance single- and multi-axis applications.
Smooth motion at low speeds
Perhaps as importantly, the arrangement of four raceways, each set with a 45-degree contact angle, ensures equal load capacity while minimising frictional losses, with low breakaway forces. This helps to produce smooth, easily controlled operation, even at extremely slow speeds, and plays a crucial role in providing an extended operating life with minimal maintenance.
Each of the LLT profile rail guides is robustly constructed from inductive and case-hardened steel, and is supplied pre-lubricated, with specially developed double-lip seals at either end of each carriage, plus side and inner seals to ensure that lubricants are retained and contaminants are excluded. Operating temperatures range from -20 to +80degC, although each unit can withstand temperatures of up to 100degC for short periods.
Additionally, SKF supplies an extensive range of accessories and provides full technical and applications support from its global network of customer support and manufacturing centres.
For more information, download the LLT brochure (6.3MB PDF).
