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Clutches

added to the clutch assembly. How-ever, the calculated race deflection at any set torque varies dramatically between the uniform pressure and discreet loading methods. Theory indicates that the discreet loading method offers greater accuracy. As such, for our example one would ex- pect Design Alternative 11 to out- perform Design Alternative 6, and Design Alternative 12 to outper- form both in terms of torque-carry- ing capabilities.In fact, bench testing validatesthese conclusions. With test fixtures an engineering team can observe torque versus angular displacement over time for all design alternatives. To continue with our example, theseresults are shown in tables. The max- imum torque calculations have an embedded service factor to allow a 1,000,000-cycle rating. As such, the actual maximum torque is signifi- cantly greater. Testing shows that the torque-carrying capability of each clutch increases as contact stress and deflection are reduced. Discrete load approximations also indicate these reductions; this veri- fies its validity and accuracy in pre- dicting the power density of a me- chanical clutch for the most realistic evaluation when compared to actual applications.

THE PROCESSWE’RE DESCRIBING

Design and customization requireintense collaboration. Inquiryteams composed of cross-func-tional groups should meet regu- larly to evaluate progress. A proj-ect management model shouldmanage special inquiries through- out the OEM and contract man- agement process. A clutch spe-cialist might act as a single point-of-contact and interface with an application team made up of anapplication engineer, a design en-gineer, a procurement represen- tative, industrial engineers, aproduct manager, and a plant oroperations representative.After successful collaborationbetween the clutch manufacturerand designers (including designiterations, analyses, and bench testing) the best design alternativeshould then be tested on a dy-namometer; this dynamometer test should simulate real-life con-ditions as seen in the field. Theresults often prove successful, as the selected cam clutch can out-last other clutches by hundreds ofhours. MSD Emerson Power Transmission 620 S. Aurora Street Ithaca, New York 14850 Customer Service: 1-800-626-2120 Technical Services: 1-800-626-2093 www.emerson-ept.com
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