Product designers using EC bands to hold bearings in position but experiencing problems at temperature extremes may find a ready solution by using tolerance rings for more demanding applications
Product designers and manufacturers using EC bands to hold bearings in position but experiencing problems at temperature
extremes may find a ready solution by using tolerance rings for more demanding applications.
Explains Jim Smith, general manager of market leading Rencol Tolerance Rings: “Like EC bands, tolerance rings allow push-fit assembly and accommodate tolerance variations in housings.
However, as they are steel rather than plastic they continue to operate effectively well beyond the temperatures at which the performance of plastic bands may become suspect and also they do not suffer from the embrittlement associated with thermal cycling of EC bands.” Typically EC bands may move into the ‘risk’ area at temperatures above 150C or become brittle below minus 30C, depending on the materials used.
Tolerance rings, essentially spring steel fasteners, have a series of wave forms around their circumference which locate against the surfaces of annular components.
Retention of mechanical properties in tolerance rings is dependent upon the type of steel used.
Carbon steel rings retain their properties up to 230C.
This rises to 290C for stainless steel and to upwards of 600C when exotic alloys are used.
There is effectively no lower temperature limit on their performance.
Tolerance rings are of similar cost to EC bands but require the introduction of discrete automated machinery when used to replace band mounts.
However, in volume applications these costs are likely to be offset by the benefits deriving from increased product performance and reduced maintenance.