The manufacturer of miniature robotic systems was faced with a problem when trying to introduce pre-loading of some miniature bearings in an exoskeleton application. Because the assembly relied upon ultra-thin wall bearings, the supporting bearing faces were little more than 1 mm wide and the axial space for the pre-load assembly was extremely restricted. With the axial and radial space at such a premium, the use of a conventional wavy washer and circlip combination was precluded since the combined thickness and the effective diameter, including the lugs, of a conventional circlip was unacceptable within the existing space envelope.
TFC’s technical team advised using a single component to provide a compact lightweight solution. The Smalley Wavering® is a spiral formed retaining ring (or circlip) but with the additional feature of compressibility. Designed to fit in a groove, it applies pressure in two directions against the groove wall and against the assembled components. In this application, the Wavering® was able to provide take-up for tolerance build-up and eliminate looseness as a consequence of vibration during operation. Furthermore, despite the design being bespoke to the application, the no-tooling method of manufacture meant there were no additional tooling costs and long lead times involved.
The use of a TFC Smalley Wavering® meant the customer was able to improve the reliability of his product without the need to incur the considerable costs involved in the modification of the assembled components. The constancy of the force with the TFC product at operating height, when compared to a conventional die-stamped wavy washer, further improved the reliability of the customers™ product. In addition, the application of a single component also reduced assembly time and removed the risk of error during assembly.