Linear Bearings run dry for over 100 million overruns.

Press Release Summary:

Anti-friction, precision DryRunner bearings are free of organic, sulfur-containing solid and soft metal coating lubricants. Products' rails have running surfaces coated with abrasion-resistant tungsten carbide, and available sizes include RN3, RN4, RN6, RNG4, and RNG6. Max lengths are available up to 900 mm, and max speeds of 1 m/s and max accelerations up to 150 m/s² can be reached. Operating temperature ranges from -40 to +80°C.

Original Press Release:

"Dryrunner" Family Of Linear Bearings Is Schneeberger's Answer To Increased Market Demand For Dry Running Linear Guides

SUBJECT: New Product/Design Engineering/OEM Manufacturing

Bedford, MA, October 14th, 2003--Schneeberger, Inc.- announced a new line of Dry Running anti-friction precision Linear Bearings- DryRunner- that are absolutely free of organic lubricants, sulfur-containing solid lubricants such as MoS2 or WS2 and are also free of soft metal coating lubricants. While the running surfaces in standard linear bearings without organic lubricants are completely destroyed after only 10,000 rolling element overruns, Schneeberger DryRunner bearings run dry for more than 100 million overruns. This represents an improvement by four orders of magnitude in dry running lifetime. Lubricant-free linear bearings are desirable in applications requiring a clean environment or where periodic lubrication is not practical.

At the heart of Schneeberger DryRunner products are rails with running surfaces coated with a very hard and abrasion resistant thin film coating of tungsten carbide. This coating has an excellent adhesion to the steel surface, a low coefficient of friction against a steel counter body, and a very high resistance to surface fatigue. The rails are coated in a PVD process (physical vapor deposition) and applied under very clean and well-controlled high-vacuum conditions.

Because cage creep has been identified as a serious issue with dry running linear bearings, the same cage centering technology featured in the Schneeberger Formula S Bearing is also included with DryRunner. Cage creep occurs in cross roller type bearings that are subject to high accelerations, especially in vertical orientations with oscillatory motion. Once a cage migrates out of position, the result is reduction of travel and eventual damage as it repeatedly contacts the end piece and skids back. With the Formula S, Cage Creep is completely eliminated.

The DryRunner is available in sizes RN3, RN4, RN6, RNG4, and RNG6 (the numbers indicating the diameter of the rolling element, rollers or balls, in millimeters) and maximum lengths are available up to 900mm. Maximum speeds of 1 m/s and maximum accelerations up to 150 m/s² can be reached. Operating Temperatures are from -40°C to +80°C (120°C for short intervals).

Cross roller linear bearings offer extreme smoothness and virtually zero friction in a low-profile package. Compared to recirculating type linear bearings, cross roller guides have no pulsation effect caused by the rolling elements entering and leaving the bearing load zone. Schneeberger manufactures six types of linear bearings including the first standardized linear bearing in the world-Type R. The complete line up which includes cross roller bearings with a zero-cage-creep assist option (Formula S) and needle bearings, consists of Type R, RN, RNG, RD, N/O, and M/V.

Schneeberger Inc., one of four subsidiaries of W. Schneeberger AG, headquartered in Switzerland, markets precision linear motion components and systems for demanding applications. Products include ball and cross-roller bearings, miniature slides and rails, profile guides, automated linear and rotary modules, multi-axis positioning systems, and precision ball screws. Based in Bedford, MA, Schneeberger, Inc sells directly through regional sales offices located throughout the US. For more information, contact Schneeberger at 1-800-854-6333 or visit

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