The tolerance ring manufacturer Rencol has completed a research programme which, it claims, has shown that motors that use tolerance rings to mount bearings produce less vibration and noise than traditional press-fit and glue alternatives, and that they last longer.

Initial results from the research suggest that because tolerance ring joints are less stiff than those using press-fit or glue mounting, the force transmitted through the bearing to the motor housing is reduced. In addition, the tolerance ring mount absorbs more vibration energy, resulting in lower noise levels.
 
“Glue and press fit bearing mounts could become a thing of the past,” predicts Stuart Kelly, Rencol’s appliance product manager. “Tolerance rings offer better repeatability, lower RMS noise level, lower RMS vibration level at high speeds, and the ability to control the frequency band in which the resonance occurs.”
 
Bristol, UK, based Rencol, owned by Saint-Gobain Performance Plastics, says that tolerance rings can help motor manufacturers to cut costs in other ways. For example, the radially sprung rings can allow them to relax housing tolerances and to use “as moulded” parts, rather than having to invest in costly finishing operations to achieve tight tolerances. The improved bearing life also allows lower quality, cheaper bearings to be used, while maintaining a similar life to more expensive bearings.

Another attraction is that motors assembled using tolerance rings can be taken apart more easily than those that have been glued together, making recycling easier.