汽车专业英语(幻灯片)Chapter 5 MT(3.3.1).ppt

1)The modern automobile engine is a powerful,lightweight,and dependable powerplant.However,it is not perfect for three reasons.First,modern engines do not produce much torque at low engine speeds.Second,engines produce maximum torque between 2000-3000r/min.As a result,engines operate best only within this fairly narrow range.Third,much more force is needed to move a car from rest than to keep it moving once it is started.Thus,the vehicle needs a wider range of torque than is available from the engine.,新型的汽车发动机动力强劲、质量轻便而且动力性能可靠。然而它美中不足的原因有三个。首先，新型发动机低速时产生的转矩较小其次，发动机在每分钟2000-3000转时转矩最大结果，发动机只能在这个相当狭窄的转速范围内工作良好第三，起动汽车比它起动后保持其运动需要的力大因此，汽车需要的转距比发动机提供的转距范围大,Review 1:Why is a transmission needed in an automobile?,Review 2:Whats the function of transmission?,Changes the engine torque,Reverses the vehicle movement,Disengages the drive,3.3 transmission,Review 3:List the types of transmission.,Finite,Infinite,MTManual Transmission（手动变速器）,ATAutomatic Transmission（自动变速器）,AMTAutomatic Mechanical Transmission（液力机械变速器）,CVTContinuously Variable Transmission（无级变速器）,2)In simple terms,a transmission multiplies engine torque and-through gears-sends that power to the drive axle.A driver shifts or changes the gears to increase or decrease the torque produced by the engine.,简而言之，变速器利用齿轮扩大发动机的扭矩，向驱动桥传递动力。驾驶员通过换挡来升高或降低发动机的输出扭矩。,Review 4:Whats the meaning of gear ratio?,DriveGear,DrivenGear,3.3.1 manual transmission,Review 5:List the mesh methods of manual transmission.,Sliding-mesh TransmissionConstant-mesh TransmissionSynchro-mesh Transimission,Sliding-mesh transmission:Although this type is rarely used today,it is included because the gear layout forms the basic construction of most modern manual gearboxes.The spur gears are mounted on four shafts:primary shaft(input shaft),layshaft(countershaft),mainshaft and reverse idler shaft.,尽管现在几乎不使用滑动啮合变速器，但在这里仍然要提及，因为它是目前大多数手动变速器的雏形。直齿圆柱齿轮装在四个轴上：输入轴，中间轴，输出轴和倒档轴,Review 6:List the types of transmission gear.,Bevel gear 锥齿轮,Helical gear 斜齿轮,Double helical gear 人字齿轮,Pinion gear 小齿轮,Hypoid gear 准双曲面齿轮,Planetary gear 行星齿轮,External gear 外啮合齿轮,Internal gear 内啮合齿轮,4)Sliding-mesh transmission:In the case of a sliding-mesh gearbox,gear changing demands skill if noise is to be avoided.Crashing(or clashing)of the gears as the result of a bad change suggests the reason why this type is often called a crash type gearbox.,对滑动啮合变速器来说，换挡时要避免噪声是需要技巧的。齿轮打齿是由换挡不当引起的，这也是滑动啮合变速器经常被称为“碰撞”型变速器的原因。,5)constant-mesh transmission:This type uses helical or double helical gears which are always in mesh.The mainshaft gear wheels are mounted on bearings and when a gear is required the mainshaft gear is locked to the shaft by a dog clutch.,常啮合变速器采用斜齿轮或人字形齿轮，这些齿轮总是处于啮合状态。输出轴上的齿轮安装在轴承上，换挡时接合套使输出轴齿轮和输出轴锁止在一起。,6)constant-mesh transmission:Although the mechanical efficiency is lower the helical gears are quieter and any damage resulting from a bad gear change occurs to the dog teeth instead of the actual gear teeth.,尽管斜齿轮的机械效率较低，但其工作噪声较小，而且由于换挡不当所引起的任何损害都不会作用在换挡齿轮的轮齿上，而是作用在接合齿圈的轮齿上。,7)synchro-mesh transmission:As the name suggests this type has a synchronization device which equalizes the speeds of the two members that have to be meshed to obtain the gear.The layout is similar to the constant-mesh but has friction cones fitted between the dog clutch and the gear wheel.,顾名思义，同步啮合变速器带有同步装置，使得换挡时要啮合的两齿轮转速达到相同。同步啮合变速器的结构与常啮合变速器类似，不同之处是在接合齿圈和齿轮之间有摩擦锥面。,8)synchro-mesh transmission:The operation of the friction device performs a duty which,in older designs,was carried out by the driver during double-declutching.The synchro-mesh gearbox gives a simpler,quieter and quicker gear change.,在老式变速器上，（同步器）摩擦装置完成的工作要通过驾驶员利用两脚离合来实现。同步啮合变速器使得换挡更为简单、安静而快捷。,Review 7:List the types of manual transmission.,Two-shaft MT,Input shaft,Main shaft,Reverse idler shaft,Input shaft(primary shaft),Main shaft,Countershaft(layshaft),Reverse idler shaft,Three-shaft MT,一挡二挡三挡四挡五挡倒挡,Review 8:List the gear shift actions of MT.,1stGear,Gear shift actions of three-shaft MT,2ndGear,3rdGear,4thGear,5thGear,ReverseGear,Review 9:List the operating system types of MT.,Direct operating system,Remote operating system,Self-lock System,Inter-lock System,Reverse-lock System,Review 10:Whats the function of Power Transfer.,To transfer the engine power to every driving axle.,