上泽充通大学 LECTURE 12 Gears-Design for Strength 齿轮强度设计 Covered Cha5 and Cha6 In Mechanical Engineering Design 上游文大学 outline SCHAI IAO TONG UNIVEROITY 1.Forces on Gears 2.Failure types of gears 3.Material selection of gear 4.Fundamental theories for gearing strength
1 Gears-Design for Strength 齿轮强度设计 LECTURE 12 Covered Cha5 and Cha6 In Mechanical Engineering Design outline 1.Forces on Gears 2.Failure types of gears 3.Material selection of gear 4.Fundamental theories for gearing strength
上海文通大学 Forces on gears Forces on spur gears Forces on helical gears Forces on bevel gears Forces on worm gears Refer to Chapter 5 in Mechanical engineering design 上游文大学 ANGHAI HAO TONG UNIVEROIT H W,=33000- +3+3→ where W.transmitted load,Ibf H=power,hp V=pitch-line velocity,ft/min 60000H W,= ndn where W,=transmitted load,kN H=power,kW d=gear diameter,mm n=speed,rev/min 3*15
2 Refer to Chapter 5 in Mechanical engineering design Forces on spur gears Forces on helical gears Forces on bevel gears Forces on worm gears Forces on gears
上泽充通大学 Forces on gears Forces on spur gears Gear 直齿圆柱齿轮传动受力分析 啮合线 Pinion (a) 上游久通大学 Forces on gears ANGHAI HAO TONG UNIVEROIT Forces on spur gears Normal: 2T Tangential F,=2T/d1 N Radial F.=Ftga N Normal F=F/cos a N a)
3 Forces on gears Forces on spur gears Normal： Tangential — 1 1 2 b n d T F Ft 2T1 / d1 N Radial — Fr Ft tg N Normal — Fn Ft / cos N Forces on gears Forces on spur gears
上浒充通大学 Forces on gears Forces on spur gears E=-F2 F=-F2 Force Direction: F-Opposite to rotation direction F2-same to rotation direction F,F2-pointing to rotating center respectively 上濟大学 Forces on gears ANGHAI HAO TONG UNIVEROIT Forces on spur gears n2
4 Ft1 Ft 2 Fr 1 Fr 2 Force Direction： Ft1- Opposite to rotation direction Ft2- same to rotation direction Fr1 、Fr2- pointing to rotating center respectively Forces on gears Forces on spur gears 2 1 n2 n1 Fr2 Fr1 Ft2 Ft1 n1 n2 Forces on gears Forces on spur gears
上泽充通大学 Shown as the fig Direction of tangential 8 forces on gear 2 and 3 ⑧o View direction ©⊙@o B Right answer 上游文大学 UGHAI HAO TONG UNIVEROI Shown as the fig 十t1F2 @⑧ Direction of tangential forces on gear 2 and 3 ⑧ Z3 View direction The answer
5 Shown as the fig Direction of tangential forces on gear 2 and 3 Right answer eg1 View direction Z1 Z4 Z2 Z3 A BCD Ft1 Ft2 Ft3 Ft4 The answer eg2 Z4 Z3 Z1 Z2 Ft2 Ft1 Ft4 Ft3 A BCD Shown as the fig Direction of tangential forces on gear 2 and 3 View direction