汽车底盘构造汽车自动变速器29－3ppt课件.ppt

第三节 行星齿轮变速机构,行星齿轮变速器的结构组成 行星齿轮变速器的工作原理 行星齿轮机构在自动变速器上的应用,一、行星齿轮机构,行星齿轮,中心齿轮,行星架,齿圈,组装图,行星齿轮机构的组成,二、行星齿轮变速原理,行星轮力平衡条件： F1=F2 F3=-2F1 三元件上的力矩分别为： 太阳轮M1=F1r1 =z2/z1=r2/r1, r3=(r1+r2)/2 齿圈M2=F2r2=F1r1 行星架 M3=F3r3=-(+1)F1r1 能量守恒三元件输入和输出功率的代数和等于零M11+M2+M3=0 n1+n2-(1+)n3=0,r,1.行星齿轮机构变速比计算,传动比i=从动件齿 数/主动件齿数 n1+n2-(1+)n3=0,2.变速原理（加速）,当太阳轮固定，行星架输入，齿圈输出时传动比为： n1+n2-(1+)n3=0 n1=0 i=n3/n2=/(1+1/)1 为超速传动 行星架和齿圈转向相同。,3.变速原理（加速）,当齿圈固定， 行星架输入， 太阳轮输出时 为超速传动， 传动比为： i=n3/n1=/(1+)1 行星架和太阳 轮转向相同。,4.变速原理（减速）,当齿圈固定， 太阳轮输入， 行星架输出时 为减速传动， 传动比为： i=n1/n3=1+ 行星架和太阳 轮转向相同。,5.变速原理（减速）,当太阳轮固 定齿圈输入， 行星架输出时 为减速传动， 传动比为： i=n2/n3=1+1/ 齿圈和行星架 转向相同。,6.变速原理（倒挡）,当行星架固定， 太阳轮输入， 齿圈输出时， 为减速传动， 传动比为： n1+n2-(1+)n3=0 n3=0 n1/n2=- 太阳轮和齿圈 转向相反。,7.转速及旋转方向,Planetenübersetzung Formeltabelle,三、行星齿轮机构在自动变速器上的应用,有三个行星排，可组合出四个档位 不同行星排有的元件是公用的 固定元件的动作由制动器和单向离合器完成,15,Automatic Transmission Gearsets,16,Simple Gear Set,A planetary gear set has three major components: A sun gear in the center, A planet carrier with two or more pinion gears, and A ring/internal gear. These are also called members.,Ring/Internal Gear,Sun Gear,Carrier with Planet Pinion Gears,17,Connections, Input,At least one, or two, of these members will be connected to the torque converter through a multidisc clutch. It can be the input when the clutch is applied. This ring/ internal gear can be driven by the forward clutch,Front Ring/ Internal Gear,Forward Clutch,Animation: Clutch Operation,18,Connections, Output,At least one of the members will be connected to the transmission output shaft so it can transfer torque to the final drive. Splines are used to connect this front carrier to the output shaft. Note that a complete planetary gearset is shown with all three members.,Output Shaft,Front Carrier,Splines,19,Connections, Reaction,When a gear ratio change is desired, one of the members must be held stationary in reaction. This carrier can be held by a roller clutch or multidisc clutch. A band is also used to hold the reaction member.,Rear Carrier with Lo & Rev. Clutch Hub,Rear Clutch Housing,Roller Clutch,Animation: One-Way Roller Clutch,20,Carrier with Pinions,This carrier has four pinion gears. The carrier is constructed so that it can be held in reaction by a multidisc clutch. It is also connected to another gearset member.,Hub for Lo and Reverse Clutch,Planet Pinion Gear,21,Planet Pinions,The pinion gears are mounted in the carrier so they can rotate freely on their shaft. Parts of a carrier are shown.,Pinion Gear,Needle Bearings,Pinion Pin/Shaft,Thrust Washer,Thrust Washer,22,Simpson Gear Set,This gear set combines portions of two simple gear sets as shown. The front ring gear and sun gears are inputs. Some internal parts are not shown,23,Ravigneaux Gearset,Most transmissions use a more complex gearset. Some use a Ravigneaux design that has two sun gears of different sizes and a carrier with two set of planet pinions, a long and a short set. This gearset can produce four forward speeds plus a reverse.,Ring Gear,Long Pinion Gear,Short Pinion Gear,Large/Front Sun Gear,Small/Rear Sun Gear,Carrier,24,Ravigneaux Gearset, Exploded,Reverse Sun Gear,Forward Sun Gear,Ring Gear,Short Pinion,Long Pinion,This AOD-E gear set has four forward speeds plus reverse and neutral.,Carrier,25,Simpson Gearset,This gearset is used in many 3-speed transmissions. It uses two planetary sets with a common sun gear.,Sun Gear,Rear Ring/ Annulus Gear,Rear Carrier,Front Ring/ Annulus Gear,Front Carrier,26,Four Speed Gearset,This modern 4-speed transmission uses a complex gearset. Two planetary sets are used with the ring/annulus gear of each set combined with the carrier of the second set.,Front Sun Gear,Rear Sun Gear,Rear Carrier & Front Annulus/ Ring Gear/Output Shaft,Front Carrier & Rear Annulus/ Ring Gear,27,Shift Control,Automatic transmissions use different driving devices, usually multiplate clutches, to send the power flow to the proper gearset member and different reaction devices to hold the proper member in reaction. These members are applied or released to get the proper gear ratio.,28,Shift Control,Automatic trans- missions use differ-ent driving devices, usually multiplate clutches, to send the power flow to the proper gearset member and differ-ent reaction devices to hold the proper member in reaction.,29,Planetary Operation,This chart shows how a simple planetary gearset can produce six different gear ratios depending on which member is driven or held. In addition to the three reduction or overdrive (OD) or forward or reverse ratios, a direct drive, 1:1, ratio occurs if two members are driven. Neutral results if no members are driven.,#1: #2: #3: #4: #5: #6:,