Lecture7-1.ppt

Chapter 7 Gear Trains (轮系) 7.1.1 Classification of gear trains: Gear train with fixed axes(定轴轮系) (ordinary gear train) This can further be divided into: The gear trains with fixed non-parallel axes can also be divided into: (2) Epicyclic gear train(周转轮系)---- at least one gear axis rotates around the other axis. Epicyclic gear trains can further be divided into: (2.1) Elementary epicyclic gear trains Planet carrier(行星架,系杆,转臂) ： The link carrying planet gears is called the planet carrier, denoted by H. Sun gears(太阳轮,中心轮)：engage with planet gears and rotate around the same fixed axis as that of the planet carrier, e.g., gear 1, 3. There is only one planet carrier, two sun gears, and one or more planet gears in an elementary epicyclic gear train. Elementary epicyclic gear trains can be divided further: F=3n-2PL-Ph =3*3-2*3-2=1 Planetary gear train is an elementary epicyclic gear train with F = 1. Sun gear 3 is fixed with the frame. Sun pinion 1 is fixed with the frame. (2.1.2) Differential gear train(差动轮系): (2.2) Combined gear trains(复合轮系) (1) Gear train with fixed axes(定轴轮系) There is only one planet carrier, two sun gears, and one or more planet gears in an elementary epicyclic gear train. * A transmission system by more than one pair of gears is called a gear train. --------the positions of all gear axes in a gear train are fixed. (1.1) (1.1) gear trains with fixed parallel axes (1.2) (1.2) gear trains with fixed non-parallel axes. (1.2.1) The directions of input shaft and output shaft are parallel. (1.2.2) The directions of input shaft and output shaft are not parallel. (2.1) Elementary epicyclic gear trains(基本周转 轮系) (2.2) Combined gear trains(复合轮系)  contains at least one elementary epicyclic gear train. Planet gear(行星轮) is a gear the axis of which rotates around the fixed axis. The gear 2 is a planet gear. Sun gears and the plan