elastomer for spring

A plastic belleville washer makes an exquisite end play adjuster in an electric motor. The trick is selecting the right material. I used acetal in one application. Relaxation will occur as with any plastic.

Acetal is normally the best choice for a spring where thermoplastics are used and the temperatures are moderate. There is a very extensive precedent in the use of acetal for springs in things like in return springs for the keys on keyboards, springs in retractable ball point pens etc.

If higher temperatures are seen, and thermosets are viable, then anything that cross-links, like polyurethane, silicone or rubber, will tend to have better creep resistance. Rubbers and urethanes are used as load bearing bushes in cars, and the original Mini Minor had rubber springs for suspension.

Regards
pat pprimmer@acay.com.au
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