Concept explainers
Spur-gear teeth have rolling and slipping contact (often about 8 percent slip). Spur gears tested to wear failure are reported at 108 cycles as Buckingham’s surface fatigue load-stress factor K. This factor is related to Hertzian contact strength SC by
where ϕ is the normal pressure angle. Cast iron grade 20 gears with
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Shigley's Mechanical Engineering Design (McGraw-Hill Series in Mechanical Engineering)
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