Differential Thermal Expansion
Tolerance Ring in a housing

Tolerance Rings are used with great success in compensating for differential thermal expansion of mating parts. A prime example would be a case where a steel bearing is in an aluminum housing and the tolerance ring prevents outer race rotation. Other examples include: silicon carbide bushings or sleeves mated to steel housings/shafts, and glass filled plastic impellers to shafts. Tolerance rings maintain retention and minimum torque values, and may accommodate wide variations in diameter without overstressing brittle components.


The graph above illustrates the superior performance of the Tolerance Ring in retaining a 2″ diameter ball bearing in an aluminum housing. With  .0012″ traditional interference fit, an installation force of 500 lbs is required. The bearing becomes loose at a temperature of 170F. With the Tolerance Ring, an initial installation force of only 320 lbs is required, and retention remains high at 230 lbs even at 270o F!

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