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Q1. (50p) An external speed-reducing helical gear set transmits the input power of 6 kW at 600 rpm. . Name Description pinion 1.25 gear 1.25 Ko overload Specifications: Material : Grade 1, through-hardened steel Hardness: 390 Brinell for pinion and 300 Brinell for gear. Normal module is 3, normal pressure angle is 20° and helix angle is 25°. They have 20 and 30 teeth. Face width is 35 mm. Kv dynamic 1.22 1.22 Ks size 1 1 Кн load-dist. 1 1 . Ye temperature 1 1 Yz reliability 0.89 0.89 Ке 1 1 rim-thickness bending geometry Y ? ONLY FOR THE GEAR: a) (5p) Find the geometry factors. b) (5p) Find the stress cycle life factors. c) (5p) Determine the hardness ratio factor d) (5p) Find AGMA strengths. e) (20p) Find the factors of safety. f) (10p) Compare the factors of safety and determine the cause of failure. YN bending life ? 15000 h, use the lower limit ZE elastic coef. ? for steel- steel ZR surface 1 1 Z wear geometry ? load- sharing, my=0.40 Zw hardness ratio ? ZN wear life ? 15000 h, use the lower limit