Ring of confidence helps avert catastrophic failure threat

The world of motorsport presents designers with some specific challenges and, when a leading manufacturer of specialist gear technology was faced with circlip failure on an idler shaft, an alternative solution was required - as TFC, supplier of fasteners and supply chain solutions, explains.

"It was discovered the 25mm diameter shaft intermittently exceeded over 15,000 rpm, causing the conventional snap-ring, responsible for maintaining the assembly, to come out of the groove and cause catastrophic failure."

Self-locking facility

The technical sales engineering team at TFC, supplier of fasteners and supply chain solutions, recommended using a variant on the Smalley Spirolox Retaining Rings that included a self-locking feature. “This variant makes them ideal for applications where high rotational speeds are involved or, where the effects of vibration, rapid acceleration or impact loading is problematic,” says TFC.

Self-locking rings provide a mechanical interference via a small tab on the ring that locks into a corresponding slot in the opposite turn and prevents the ring from expanding out of the groove as a result of centrifugal forces at high rotational speeds.

Fast replacement

As the same method of manufacture, used for standard parts, was employed to produce the self-locking ring, the replacement component, which fits directly into the existing shaft groove, was available within 3-4 weeks. “The customer was able to acquire a cost-effective solution, without the need to manufacture expensive mechanical restrictor devices required to prevent the original circlip from failing under extreme operating conditions.”