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Product Briefing Outline: A unique Roller Pinion System (RPS) from Nexen Group, Inc., allows machine designers to incorporate highly accurate linear and rotary motion-control functions with zero backlash and speeds as high as 11 meters per second (36.1 feet per second).  The patented RPS technology can replace typical rack and pinions, linear motors, spur gears, chain/belt drives and ball-screws in critical motion-control applications that require high speed, great accuracy, and low maintenance and noise.

Problem: Operating on either a toothed linear track or ring gear, the Nexen RPS features a drive pinion with bearing-supported rollers that move smoothly along the face of the rack or gear-tooth profile, producing very low noise, vibration and wear.  The design maintains opposing contact with two or more teeth at all times, offering backlash-free performance in both directions with no cumulative or thermal-expansion error.

Solution: The accuracy of the Roller Pinion System is controlled by the way in which the roller pinions engage the linear toothed track or the ring gear.  Behaving more like a cam than the sliding action of a typical spur gear, the roller pinions follow the profile of the specially shaped teeth in such a way that two rollers are always in oppositional contact.  This eliminates backlash and reduces noise, vibration and wear.  The typical useful life of the Roller Pinion System is estimated to be as high as 28,000,000 meters of travel (94,000,000 feet).  After this distance, it will continue to operate, but with decreasing accuracy.  Linear track sections can be joined together to total any reasonable length with no sacrifice in accuracy.  In addition, the ring gear can be manufactured in segments that can be joined together to create large diameters with no loss of precision.

Applications: The RPS is suited to long runs and large motion-control applications.  

Platform: Both the ring-gear and the linear Roller Pinion Systems are available with a ‘Raydent’ surface treatment that provides stainless steel-like performance without the high cost and low surface hardness typical of stainless steel.  Unlike a coating, ‘Raydent’ is a cryogenic process that permeates the metal and permanently bonds with it to form a 1mm-deep oxide ceramic layer that resists corrosion and wear.

Availability: February 2008 onwards.