Posted to News on 5th Oct 2009, 09:47
New anti-fretting surface treatment for hollow drive shafts
Nord Drivesystems has developed a specialised surface treatment option for hollow drive shafts that resists the formation of fretting rust or friction corrosion - thereby reducing wear and facilitating the easy removal of gear motors for gearbox and motor servicing or replacement.
Fretting rust or friction corrosion occurs in fixed mechanical joints under load and vibration where at least one surface material contains iron. While it is commonly associated with bolted tension members in structures such as bridges, the phenomenon is also seen in splines and drive shafts (even stainless steel versions) where the clamped drive and driven shaft surfaces experience microscopic levels of relative motion.
The oxidised debris is abrasive and contributes to increased wear and, much more of a problem for drive shafts, the tiny fragments become compressed between the surfaces - often making removal extremely difficult and sometimes resulting in costly shaft damage.
Nord's RS coating option, available across its range of gearmotors, produces an extremely hard-wearing and corrosion-resistant layer approximately 10 microns thick that reduces surface friction characteristics and significantly reduces the formation of fretting rust. The treatment is claimed to allow effortless gearmotor shaft removal and eliminate the potential for damage to the insert shaft, thereby saving costs by minimising maintenance and repair times.
