Tolerance rings answer tricky problems

Jointing annular components can give rise to numerous problems and, all too often, demand solutions which are certainly ingenious but also complex.

Jointing annular components can give rise to numerous problems and, all too often, demand solutions which are certainly ingenious but also complex.

Increasing numbers of component manufacturers are now finding that switching to the use of tolerance rings can provide a simpler and more cost-effective approach.

The tolerance ring waveforms create an interference fit between mating components.

The waveforms and other important criteria, such as ring thickness and hardness, are designed with ring specialist and component manufacturer working closely together on development.

Tolerance Rings are increasingly used in automotive applications with approximately 30 million used last year, of which 50% were used in steering column applications.

These include mounting the anti theft collar, to provide torque overload protection of the lock mechanism, torque overload protection of the drive gear in electric power steering, axial resistance in steering column collapse and changing the NVH characteristics on steering column bearing mounts.

Tolerance rings are not limited to just steering column applications and are typically found throughout the vehicle for mounting gears in seat adjusters, power steps, electric mirrors and power lift gates.

Rencol Tolerance Rings now leads the way in problem solving solutions.

Product innovations include the use of waves, dimples, square profiled waves and sprung fingers; these are currently being used to mount electric motors inside throttle and EGR castings.

All customers have different reasons for using tolerance rings.

Some of these benefits include secure mounting across temperature range, relaxed tolerances on mating components, improved vibration characteristics of mounting method, ease of assembly, improved concentricity of mounting method, torque overload protection of gears, elimination of complex machining operations, removal of backlash and ability to allow angular misalignment.

Although the above list of benefits is large, it is by no means complete.

The use of tolerance rings to innovate overall design issues enables designers to achieve a cost effective means of solving problems, while adding substantial benefits to the overall end product.

Tolerance rings are deceptively simple devices, costing just a few pence a unit in volume production.

In addition to custom designed rings, a number of standard rings are also available for common applications such as mounting bearings in electric motors, fans, pulleys and impellers.

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