机械毕业设计英文外文翻译547运动型7速双离合器变速器系统

CLUTCHThe engine produces the power to drive the vehicle. The drive line or drive train transfers the power of the engine to the wheels. The drive train consists of the parts from the back of the flywh eel to the wheels. These parts include the clutch, th e transmission, the drive shaft, and the final drive assembly (Figure 8-1).The clutch which includes the flywheel, clutch disc, pressure plate, springs, pressure plate cover and the linkage necessary to operate the clutch is a rotating mechanism between t he engine and the transmission (Figure 8-2). It operates through friction which comes from contact between the parts. That is the reason why the clutch is called a friction mechanism. After engagement, the clutch must continue to transmit all the engine torque to the transmission depending on the friction without slippage. The clutch is also used to disengage the engine from the drive train whenever the gears in the transmission are being shifted from one gear ratio to another.To start the engine or shift the gears, the driver has to depress the clutch pedal with the purpose of disengagement the transmission from the engine. At that time, the driven members connected to the transmission input shaft are either stationary or rotating at a speed that is slower or faster than the driving members connected to the engine crankshaft. There is no spring pressure on the clutch assembly parts. So there is no friction between the driving members and driven members. As the driver lets loose the clutch pedal, spring pre ssure increases on the clutch parts. Friction between the parts also increases. The pressure exerted by the springs on the driven members is controlled by the driver through the clutch pedal and linkage. The positive engagement of the driving and driven members is made possible by the friction between the surfaces of the members. When full spring pressure is applied, the speed of the driving and driven members should be the same. At themoment, the clutch must act as a solid coupling device and transmit al l engine power to the transmission, without slipping.However, the transmission should be engaged to the engine gradually in order to operate the car smoothly and minimize torsional shock on the drive train because an engine at idle just develops little power. Otherwise, the driving members are connected with the driven members too quickly and the engine would be stalled.The flywheel is a major part of the clutch. The flywheel mounts to the engine’s crankshaft and transmits engine torque to the clutch assembly. The flywheel, when coupled with the clutch disc and pressure plate makes and breaks the flow of power from the engine to the transmission.The flywheel provides a mounting location for the clutch assembly as well. When the clutch is applied, the flyw heel transfers engine torque to the clutch disc. Because of its weight, the flywheel helps to smooth engine operation. The flywheel also has a large ring gear at its outer edge, which engages with a pinion gear on the starter motor during engine cranking.The clutch disc fits between the flywheel and the pressure plate. The clutch disc has a splined hub that fits over splines on the transmission input shaft. A splined hub has grooves that match splines on the shaft. These splines fit in the grooves. Thus, t he two parts are held together. However, back-and-forth movement of the disc on the shaft is possible. Attached to the input shaft, At disc turns at the speed of the shaft.The clutch pressure plate is generally made of cast iron. It is round and about the same diameter as the clutch disc. One side of the pressure plate is machined smooth. This side will press th e clutch disc facing are against the flywheel. The outer side has various shapes to facilitate attachment of spring and release mechanisms. The two primary types of pressure plate assemblies are coil spri ng assembly and diaphragmspring (Figure 8-3).In a coil spring clutch the pressure plate is backed by a number of coil springs and housed with them in a pressed-steel cover bolted to the flywheel. The springs push against the cover. Neither the driven plate nor the pressure plate is connected rigidly to the flywheel and both can move either towards it or away. When the clutch pedal is depressed a thrust pad riding on a carbon or ball thrust bearing i s forced towards the flywheel. Levers pivoted so that they engage with the thrust pad at one end and the pressure plate at the other end pull the pressure plate back against its springs. This releases pressure on the driven plate disconnecting the gearbox from the engine (Figure 8-4).Diaphragm spring pressure plate assemblies are widely used in most modern cars. The diaphragm spring is a single thin sheet of metal which yields when pressure is applied to it. When pressure is removed the metal springs back to its original shape. The centre portion of the diaphragm spring is slit into numerous fingers that act as release levers. When the clutch assembly rotates with the engine these weights are flung outwards by centrifugal forces and cause the levers to pre ss against the pressure plate. During disengagement of the clutch the fingers are moved forward by the release bearing. The spring pivots over the fulcrum ring and its outer rim moves away from the flywheel. The retracting spring pulls the pressure plate a way from the clutch plate thus disengaging the clutch (Figure 8-5).When engaged the release bearing and the fingers of the diaphragm spring move towards the transmission. As the diaphragm pivots over the pivot ring its outer rim forces the pressure plate against the clutch disc so that the clutch plate is engaged to the flywheel.The advantages of a diaphragm type pres sure plate assembly are its compactness, lower weight, fewer moving parts, less effort to en gage, reduces rotational imbalance by providin g a balanced force around the pressure plate and less chances of clutch slippage.The clutch pedal is connected to the disengagement mechanism either by a cable or, more com monly, by a hydraulic system. Either way, pushing the pedal down operates the dise ngagement mechanism which puts pressure on the fingers of the clutch diaphragm via a release bearing and causes the diaphragm to release the clutch plate. With a hydraulic mechanism, the clutch pedal arm operates a piston in the clutch master cylinder. Thi s forces hydraulic fluid through a pipe to the clutch release cylinder where another piston operates the clutch disengagement mechanism. The alternative is to link the clutch pedal to the disengagement mechanism by a cable.The other parts including the cl utch fork, release bearing, bell-housing, bell housing cover, and pilot bushing are needed to couple and uncouple the transmission. The clutch fork, which connects to the linkage, actually operates the clutch. The release bearing fits between the clutch fork and the pressure plate assembly. The bell housing covers the clutch assembly. The bell housing c over fastens to the bottom of the bell housing. This removable cover allows a mechanic to inspect the clutch without removing the transmission and bell housing. A pilot bushing fits into the back of th e crankshaft and holds the transmission input shaft.Torque ConverterThe BasicsJust like manual transmission cars, cars with automatic transmissions need a way to let the en gine turn while the wheels and gears in the transmission come to a stop. Manual transmission cars use a clutch, which completely disconnects the engine from the transmission. Automatic transmis sion cars use a torque converter.A torque converter is a type of fluid coupling, which allows the engine to spin somewhat independently of the transmission. If the engine is turning slowly, such as when the car is idling at a stoplight,the amount of torque passed through the torque converter is very small, so keeping the car still requires only a li ght pressure on the brake pedal.If you were to step on the gas pedal while the car is stopped, you would have to press harder on the brake to keep the car from moving. This is because when you step on the gas, the engine speeds up and pumps more fluid into the torque converter, causing more torque to be transmitted to the wheels.Inside a Torque ConverterThere are four components inside the very strong housing of the torque converter:1. Pump;2. Turbine;3. Stator;4. Transmission fluid.The housing of the torque converter is bolted to the flywheel of the engine, so it turns at what ever speed the engine is running at. The fins that make up the pump of the torque converter are at tached to the housing, so they also turn at the same speed as the engine. The cutaway below shows how everything is connected inside the torque converter (Figure 8-6).The pump inside a torque converter is a type of centrifugal pump. As it spins, fluid is flung to the outside, much as the spin cycle of a washing machine flings water and clothes to the outside of the wash tub. As fluid is flung to the outside, a vacuum is created that draws more fluid in at the center.The fluid then enters the blades of the turbine, which is connected to the transmission. The turbine causes the transmission to spin, which basically moves the car. The blades of the turbine are curved. This means that the fluid, which enters the turbine from the outside, has to change direction before it exits the center of the turbine. It is this directional change that causes the turbine to spin.The fluid exits the turbine at the center, moving in a different direction than when it entered. The fluid exits the turbine moving opposite the direction that the pump (and engine) is turning. If the fluid were allowed to hit the pump, it would slow the engine down, wasting power. This is why a torque converter has a stator.The stator resides in the very center of the torque converter. Its job is to redirect the fluid returning from the turbine before it hits the pump again. This dramatically increases the efficiency of the torque converter.The stator has a very aggressive blade design that almost completely reverses the direction of the fluid. A one-way clutch (inside the stator) connects the stator to a fixed shaft i n the transmission. Because of this arrangement, the stator cannot spin with the fluid - i tc a n s p i n o n l y i n t h e o p p o s i t ed i re c t i o n,f o r c i ng th e f l ui d t oc h a n g ed i re c t i o n a s i t h i t s t h e s t a t o r b l a d e s.Something a little bit tricky happens when the car gets moving. There is a point, around 40 mph (64 kph), at which both the pump and the turbine are spinning at almost the same speed (the pump always spins slightly faster). At this point, the fluid returns from the turbine, entering the pump already moving in the same direction as the pump, so the stator is not needed.Even though the turbine changes the direction of the fluid and flings it out the back, the fluid still ends up moving in the direction that the turbine is spinning because the turbine is spinning faster in one direction than the fluid is being pumped in the other direction. If you were standing in the back of a pickup moving at 60 mph, and you threw a ball out the back of that pickup at 40 mph, the ball would still be going forward at 20 mph. This is similar to what happens in the tur bine: The fluid is being flung out the back in one direction, but not as fast as it was going to start with in the other direction.At these speeds, the fluid actually strikes the back sides of the stator blades, causing the stator to freewheel on its one-way clutch so it doesn’t hinder the fluid moving through it.Benefits and Weak PointsIn addition to the very important job of allowing a car come to a complete stop without stalling the engine; the torque converter a ctually gives the car more torque when you accelerate out of a Stop. Modern torque converters can multiply the torque of the engine by two to three times. This effect only happens when the engine is turning much faster than the transmission.At higher speeds, the transmission catches up to the engine, eventually moving at almost the same speed. Ideally, though, the transmission would move at exactly the same speed as the engine, because this difference in speed wastes power. This is part of the reason why cars with automatic transmissions get worse gas mileage than cars with manual transmissions.To counter this effect, some cars have a torque converter with a lockup clutch. When the two halves of the torque converter get up to speed, this clutch locks them together, eliminating the slip page and improving efficiency.离合器发动机产生动力用以驱动车辆。

附录附录A 英文文献Transmission descriptionTransmission gearbox's function the engine's output rotational speed is high, the maximum work rate and the maximum torque appears in certain rotational speed area. In order to display engine's optimum performance, must have a set of variable speed gear, is coordinated the engine the rotational speed and wheel's actual moving velocity. The transmission gearbox may in the automobile travel process, has the different gear ratio between the engine and the wheel, through shifts gears may cause the engine work under its best power performance condition. Transmission gearbox's trend of development is more and more complex, the automaticity is also getting higher and higher, the automatic transmission will be future mainstream.Automotive Transmission's mission is to transfer power, and in the process of dynamic change in the transmission gear ratio in order to adjust or change the characteristics of the engine, at the same time through the transmission to adapt to different driving requirements. This shows that the transmission lines in the automotive transmission plays a crucial role. With the rapid development of science and technology, people's car is getting higher and higher performance requirements, vehicle performance, life, energy consumption, such as vibration and noise transmission depends largely on the performance, it is necessary to attach importance to the study of transmission.Transmission gearbox's pattern the automobile automatic transmission common to have three patterns: Respectively is hydraulic automatic transmission gearbox (AT), machinery stepless automatic transmission (CVT), electrically controlled machinery automatic transmission (AMT). At present what applies is most widespread is, AT becomes automatic transmission's pronoun nearly.AT is by the fluid strength torque converter, the planet gear and the hydraulic control system is composed, combines the way through the fluid strength transmission and the gear to realize the speed change bending moment. And the fluid strength torque converter is the most important part, it by components and so on pump pulley, turbine wheel and guide pulley is composed, has at the same time the transmission torque and the meeting and parting function.And AT compare, CVT has omitted complex and the unwieldy gear combination variable transmission, but is two groups of band pulleys carries on the variable transmission. Through changes the driving gear and the driven wheel transmission belt's contact radius carries on the speed change. Because has cancelled the gear drive, therefore its velocity ratio may change at will, the speed change is smoother, has not shifted gears kicks the feeling.AMT and the hydraulic automatic transmission gearbox (AT) is the having steps automatic transmission equally. It in the ordinary manual transmission gearbox's foundation, through installs the electrically operated installment which the microcomputer controls, the substitution originally coupling's separation which, the joint and the transmission gearbox completes by the manual control elects to keep off, to shift gears the movement, realizes fluid drive.Manual transmission gear mainly uses the principle of deceleration. Transmission within the group have different transmission ratio gear pair, and the car at the time of shift work, that is, through the manipulation of institutions so that the different transmission gear pair work. Manual transmission, also known as manual gear transmission, with axial sliding in the gears, the meshing gears through different speed to achieve the purpose of torque variation. Manual shift transmission can operate in full compliance with the will of the driver, and the simple structure, the failure rate is relatively low, value for money.Automatic transmission is based on speed and load (throttle pedal travel) fortwo-parameter control gear in accordance with the above two parameters to automatically take-off and landing. Automatic transmission and manual transmission in common, that is, there are two-stage transmission, automatic transmission can only speed the pace to automatically shift, manual transmission can be eliminated, "setback" of the shift feel.Automatic transmission is a torque converter, planetary gears and hydraulic manipulation of bodies, through the hydraulic transmission and gear combination to achieve the purpose of variable-speed torque variation.Also known as CVT-type continuously variable CVT. This transmission and automatic transmission gear generally the biggest difference is that it eliminates the need of complex and cumbersome combination of variable-speed gear transmission, and only two groups to carry out variable-speed drive pulley.CVT transmission than the traditional structure of simple, smaller and it is not the number of manual gear transmission, no automatic transmission planetary gear complex group, mainly rely on the driving wheel, the driven wheel and the transmission ratio brought about by the realization of non-class change.Widely used in automotive internal combustion engine as a power source, the torque and speed range is very small, and complex conditions require the use of motor vehicles and the speed of the driving force in the considerable changes in the scope. To resolve this contradiction, in the transmission system to set up the transmission to change transmission ratio, the expansion of the driving wheel torque and speed range in order to adapt to constantly changing traffic conditions, such as start, acceleration, climbing and so on, while the engine in the most favorable conditions to work under the scope; in the same direction of rotation of the engine under the premise of the automobile can be driven back; the use of neutral, interruption of power transmission, in order to be able to start the engine, idle speed, and ease of transmission or power shift . Transmission is designed to meet the above requirements, so that the conditions in a particular vehicle stability.In addition to transmission can be used to meet certain requirements, but also to ensure that it and the car can have a good match, and can improve the car's power andeconomy to ensure that the engine in a favorable condition to increase the scope of the work of the use of motor vehicles life, reduce energy consumption, reduce noise, such as the use of motor vehicles.Today the world's major car companies CVT are very active in the study. The near future, with electronic control technology to further improve, electronically controlled Continuously Variable Transmission-type is expected to be a wide range of development and application.附录B 文献翻译变速器介绍发动机的输出转速非常高，最大功率及最大扭矩在一定的转速区出现。

毕业设计（论文）外文翻译AUTOMATIC TRANSMISSIONThe modern automatic transmission is by far，the most complicated mechanical component in today’s automobile.It is a type of transmission that sifts itself.A fluid coupling or torque converter is used instead of a manually operated clutch to connect the transmission to the engine.There are two basic types of automatic transmission based on whether the vehicle is rear wheel drive or front wheel drive.On a rear wheel drive car，the transmission is usually mounted to the back of the engine and is located under the hump in the center of the floorboard alongside the gas pedal position.A drive shaft connects the transmission to the final drive which is located in the rear axle and is used to send power to the rear wheels.Power flow on this system is simple and straight forward going from the engine，through the torque converter，then trough the transmission and drive shaft until it reaches the final drive where it is split and sent to the two rear transmission.On a front wheel drive car，the transmission is usually combined with the final drive to form what is called a transaxle.The engine on a front wheel drive car is usually mounted sideways in the car with the transaxle tucked under it on the side of the engine facing the rear of the car.Front axles are connected directly to the transaxle and provide power to front wheels.In this example，power floes from the engine，through the torque converter to a larger chain that sends the power through a 180 degree turn to the transmission that is alongside the engine.From there，the power is routed through the transmission to the final drive where it is split and sent to the two front wheels through the drive axles.There are a number of other arrangements including front drive vehicles where the engine is mounted front to back instead of sideways and there are other systems that drive all four wheels but the two systems described here are by far the most popular.A much less popular rear and is connected by a drive shaft to the torque converter which is still mounted on the engine.This system is found on the new Corvette and is used in order to balance the weight evenly between the front and rear wheels for improved performance and handling.Another rear drive system mounts everything，the engine，transmission and final drive in the rear.This rear engine arrangement is popular on the Porsche。

本科毕业设计（论文）英文资料翻译*****指导教师：孙飞豹（副教授）学科、专业：车辆工程沈阳理工大学应用技术学院2011年12月20日transmission used in automobilesA standard transmission or manual transmission is the traditional type of transmission used in automobiles. The manual or standard transmission consists of a series of gears, synchros, roller bearings, shafts and gear selectors. The main clutch assembly is used to engage and disengage the engine from the transmission. Heliacal cut gears are used to select the ratio desired the sector fork move gears from one to another by using the gearshift knob. Synchros are used to slow the gear to a stop before it is engaged to avoid gear grinding, the counter shaft hold the gears in place and against the main input and output shaft. A stick shift transmission has no torque converter so there is no need for a transmission cooler. A stick shift transmission needs a simple fluid change for proper service. (there is no transmission filter in a stick shift transmission).Transmission ShifterMost manual transmissions have one reverse gear and four to six forward gears. Some cars also have eight forward gears while thirteen to twenty-four gears are present in semi trucks. To differentiate among the available standard transmissions, they are addressed by the number of forward gears. For example, if the standard transmission has five gears, it will be referred to as 5-speed standard transmission or 5-speed standard.Typical Standard Transmission ConfigurationInside the transmission shafts contain all forward and reverse gears. Most transmissions contain three shafts: input shaft, output shaft and counter or lay shaft. Other than standard transmission, there are other transmissions like continuously variable transmission, automatic transmission and semi-automatic transmission. In the manual transmission, a pair of gears inside the transmission selects the gear ratios. Whereas, in an automatic transmission, combination of brake bands and clutch packs control the planetary gear which selects the gear ratio.If there is a provision to select a gear ratio manually in automatic transmissions, the system is called a semi-automatic transmission. The driver can select from any of the gears at any pointof time. In some automobiles like racing cars and motorcycles that have standard transmissions, the driver can select the preceding or the following gear ratio with no clutch operation needed. This type of standard transmission is known as sequential transmission. In this transmission the clutch is still used for initial take off.Clutch and Flywheel AssemblyThe main clutch plays the role of a coupling device which separates the transmission and the engine. If the clutch is absent and the car comes to a stop the engine will stall. In automobiles, the clutch can be operated with the help of a pedal located on the floor of the vehicle. In an automatic transmission instead of a clutch, a torque converter is used to separate the transmission and engine.Typical Stick Shift PatternsA desired gear can be selected by a lever which is usually located on the floor in between the driver and passenger seat. This selector lever is called the gear lever or gear selector or gear shift or shifter. This gear stick can be made to move in right, left, forward and backward direction. When the gear is placed on the N position or neutral position, no gear will be selected. To move the car in the backward direction, the R gear or reverse gear should be selected.Standard transmissions are more efficient and less expensive to produce than automatic transmissions. A Standard transmission is about 15% more efficient compared to an automatic transmission. Standard transmissions are generally stronger than automatic transmissions and off road vehicles take advantage of a direct gear selection so they can withstand rough conditions. Less active cooling is also required in manual transmission system because less power is wasted.●Popular Problem ChecksCar will not go into gearClutch disc is broken completelyInternal transmission damageFailed clutch master cylinderSeized clutch slave cylinderBroken clutch fork pivotBroken clutch cableCar goes into gear but it fades out or is slippingClutch is worn out and needs replacementClutch is oil soaked from a external engine oil leakCar makes grinding noise while operating or shifting gearsOne of the roller or thrust bearings has failedThe gear synchro is worn out not forcing the gear stop before it is engaged causing a grinding gear.A counter or main shaft bearing has failed causing misalignment of the gears●Troubleshooting Noise and ProblemsIf the vehicle is running and a whirring sound is heard, then it goes away when the clutch is depressed, the transmission input bearing has failed.If the transmission is quiet in neutral but when you depress the clutch a squeaking noise is observed, a clutch throw out bearing has failed.Tips:Never let little noises go unattended; a small noise can cause a large noise and transmission operation failure. Never overload a vehicle or tow beyond the capacity this can cause premature transmission failure.汽车变速器汽车传统变速器是那种标准的手动变速器。

附录原文：Transmission designAs we all know,automobile engine to a certain speed can be achieved under the best conditions, when compared issued by the power, fuel economy is relatively good. Therefore, we hope that the engine is always in the best of conditions to work under. However, the use of motor vehicles need to have different speeds, thus creating a conflict. Transmission through this conflict to resolve.Automotive Transmission role sum up in one sentence, called variable speed twisting, twisting or slow down the growth rate by increasing torsional. Why can slow down by twisting, and the growth rate but also by twisting? For the same engine power output, power can be expressed as N = wT, where w is the angular velocity of rotation, and T Niuju. When N fixed, w and T is inversely proportional to the. Therefore, the growth rate will reduce twisting, twisting slowdown will increase. Automotive Transmission speed gear based on the principle of variable twisted into various stalls of different transmission ratio corresponding to adapt to different operational conditions.General to set up a manual gearbox input shaft, intermediate shaft and output shaft, also known as the three-axis, as well as Daodang axis. Three-axis is the main transmission structure, input shaft speed is the speed of the engine, the output shaft speed is the intermediate shaft and output shaft gear meshing between different from the speed. Different gears are different transmission ratio, and will have a different speed. For example Zhengzhourichan ZN6481W2G manual transmission car-SUV, its transmission ratio are: 1 File 3.704:1; stalls 2.202:1; stalls 1.414:1; stalls 1:1 5 stalls (speeding file) 0.802: 1.When drivers choose a launch vehicle stalls, Plectrum will be 1 / 2 file synchronization engagement with a back stall gear and output shaft lock it, the power input shaft, intermediate shaft and output shaft gear of a stall, a stall the output shaft gear driven, and the output shaft power will be transmitted to the drive shaft (red arrow). A typical stall Biansuchilun transmission ratio is 3:1, that isto say three laps to the input shaft and output shaft to a circle.When the growth rate of car drivers choose two stalls, Plectrum will be 1 /2-file synchronization and file a joint separation after 2 stall and lock the output shaft gear, power transmission line similar, the difference is that the output shaft gear of a stall 2 stall replaced by the output shaft gear driven. 2 stall Biansuchilun typical transmission ratio is 2.2:1, 2.2 laps to the input shaft and output shaft to a circle than a stall speed increase, lower torque.When refueling vehicle drivers growth stalls option 3, Plectrum to 1 / 2 back to the free file-synchronization position, and also allows the 3 / 4 file synchronization Mobile stall until 3 in the output shaft gear lock, power can be into the shaft axis - intermediate shaft - the output shaft of the three stalls Biansuchilun, led through three stalls Biansuchilun output shaft. 3 stalls typical transmission ratio is 1.7:1, 1.7 laps to the input shaft and output shaft to a circle is further growth.When car drivers Option 4 refueling growth stalls, Plectrum will be 3 / 4 from the 3-file synchronization stall gear directly with the input shaft gear joint initiative, and power transmission directly from the input shaft to the output shaft, the transmission ratio at 1:1, that the input shaft and output shaft speed the same. The driving force without intermediate shaft, also known as direct file, the file transmission than the maximum transmission efficiency. Most cars run-time files are used directly to achieve the best fuel economy.Shift into the first interval when, in a free transmission when Biansuchilun output shaft is not locked in, they can not rotate the output shaft driven, not power output.General automotive manual transmission than the main 1-4 stalls, usually the first designers to determine the minimum (one stall) and maximum (4 files) transmission ratio, the middle stall drive by geometric progression than the general distribution. In addition, there are stalls Daodang and speeding, speeding file is also known as the five stalls.When the car to accelerate to more than car drivers with the choice of five stalls, and a typical five-transmission ratio is 0.87:1, which is driven by a pinion gear, the gear when the initiative to 0.87 zone, passive gear have been transferred to a circle of the End.Dao Dang, the opposite direction to the output shaft rotation. If one pair of meshing gears when we reverse rotation, with a middle gear, it will become thesame to the rotation. Use of this principle, we should add a gear Daodang the "media" will be rotational direction reversed, it will have a Daodang axis. Daodang installed in the transmission shaft independent crust, and the intermediate shaft parallel axis gear with the intermediate shaft and output shaft gear meshing gears, will be contrary to the output shaft.Daodang usually used for the synchronization control also joins five stalls, stalls and Daodang 5 position in the same side. As a middle gear, the general transmission Daodang transmission ratio greater than 1 file transmission ratio, by twisting, steep slope with some vehicles encountered on the progress stalls falters with a Daodang boost.Ride from the driver of the considerations, better transmission stall, stall adjacent stall more than the transmission changes the ratio of small, and easy to shift smoothly. However, the shortcomings of the stalls is more transmission structure is complicated, bulky, light vehicle transmission is generally 4-5 stalls. At the same time, transmission ratio is not integral, but with all of the decimal point, it is because of the gear teeth meshing is not caused by the whole multiples of two gear teeth can lead to the whole multiples of two meshing gears of uneven wear, making the tooth surface quality have a greater difference.Manual transmission and synchronizerManual transmission is the most common transmission, or MT. Its basic structure sum up in one sentence, is a two-axle shaft, where input shaft, the shaft axis and intermediate shaft, which constitute the main body of the transmission and, of course, a Daodang axis. Manual transmission known as manual gear transmission, which can be in the axial sliding gears, the gears meshing different variable speed reached twisting purpose. Typical manual transmission structure and principles are as follows.Input shaft also said that the first axis, and its front-end Spline driven directly with the clutch disc sets with the Spline, by the transfer of torque from the engine. The first axis of the intermediate shaft and gears meshing gears often, as long as the shaft axis to a turn, the intermediate shaft and gear also will be rotating. Vice also said intermediate shaft axis, the axis-even more than the size gear. Also known as the second output shaft axis, the axis of various sets of gear stall progress can be manipulated at any time in the role of the device and the corresponding intermediate shaft gear meshing, thus changing its speed and torque. With the endof the output shaft spline associated with the drive shaft through the drive shaft torque transmitted to the drive axle reducer.Thus, progress stalls drive transmission path is: input shaft gear often rodents - often rodents intermediate shaft gear - corresponding intermediate shaft gear - the second axis corresponding gear. Reversing the gear shaft can be manipulated by the device pick in the axis movement, and the intermediate shaft and output shaft gear meshing gears, to the contrary to the direction of rotation output.Most cars have five stalls and a Daodang forward, a certain degree of each stall transmission ratio, the majority of stalls transmission ratio greater than 1, 4 file transmission ratio of 1, known as direct stalls, and transmission ratio is less than 1 No. 5 stall called accelerated stall. Free at the output shaft gear in a position of non-engagement, unacceptable power transmission.The transmission input shaft and output shaft rotational speed to their own, transform a stall when there is a "synchronous". Two different rotational speed gear meshing force will impact the collision occurred, damage gear. Therefore, the old transmission shift to a "feet-off" approach, or stall on the location of the free stay for a while by stalls in the free position refueling doors, in order to reduce the speed differential gear. However, this operation is relatively more complicated and difficult to grasp accurate. So designers create a "synchronized," and allows synchronization through the meshing of gears to be consistent speed and smooth meshing.At present Synchronous Transmission is based on the synchronization of inertia, mainly from joint sets, synchronous lock ring, and so on, it is characterized by friction on the role of synchronization. Splice sets Genlock engagement ring gear and the ring gear when it had Chamfer (Lock angle), Genlock within the cone ring gear engagement with the question of cone ring gear contact friction. Lock and cone angle has been made in the design of an appropriate choice to be made friction cone of the teeth meshing with the ring gear quickly sets pace at the same time will have a Lock role and to prevent the gears meshing in sync before. When synchronization lock cone ring gear engagement with the question of cone ring gear after contact in the effects of friction torque gear speed quickly lower (or higher) with the same speed synchronous lock ring, the two synchronous rotation of the gear Genlock Central zero speed, thus moment of inertia also disappear, then in force under the impetus of engagement sets unhindered andsynchronization lock ring gear engagement, and further engagement with the question of gear engagement and the completion Gear Shift Process.The automatic gearboxThe automatic gearbox chooses to block the pole the equal to moving the stick shift of the gearbox, having generally below several blocks:P( parking), R( pour to block), N( get empty to block), D( go forward), S( or2, namely for 2 block soon), L.( or1, namely for 1 block soon)This several an usage for blocking a right usages coming driver the automatic gearbox is automotive of person to say particularly important, underneath let us very much familiar with once automatic gearbox eachly blockings main theme.The usage of the P ( the parking blocks)The launches the luck turns as long as choose to block the pole in driving the position, automatic gearbox car run about very easily.But park, choose to block the pole must pull into of P, from but pass the internal parking system in gearbox moves the device will output the stalk lock lives, combining to tense the hand system move, preventing the car ambulation.The usage of the R( pour to block)R a control for is pouring blocking, using inside wanting slicing recording, automatic gearbox car unlike moving gearbox car so can using half moving, so while reversing the car wanting special attention accelerating pedal.The usage of the N( get empty to block)The N is equal to get empty to block, can while starting or hour of trailer usage.At wait for the signal or block up the car will often often choose to block the pole keeps in the of D, trampling at the same time the next system move.If time is very short, do like this is an admission of, but if stop the time long time had better change into of N, combine to tense the hand system moves.Because choose to block the pole in driving the position, the automatic gearbox car has generally and all to drive the trend faintly, long hours trample the system move same as a deterrent this kind of trend, make gearbox oil gone up, the oil liquid changes in character easily.Particularly in the air condition machine work, launch the soon higher circumstance in machine bottom more disadvantageous.Some pilots for the sake of stanza oil, at made good time or go down slope will choose to block the pole pull the of N skids, this burn the bad gearbox very easily, launching the machine to revolves soon in the however because the gearbox outputs at this timethe stalk turns soon very high,, the oil pump provides the oil shortage, lubricatingthe condition worsen, burn the bad gearbox easily.The usage of the D( go forward to block)Will choose to block when is normal to drive the pole put in the of D, car can at 1 ～4 block( or 3 block) its change to block automatically.The of D drives the position most in common usely.What demand control is:Because the automatic gearbox is soon high and low with car to come to make sure to block according to the accelerator size a, so accelerate the pedal operation method is different, changing to block the hour of the car is soon too not same alike.If start hour quick accelerate the pedal tramples the bottom, rising to block the night, accelerating the ability is strong, arriving certain car soon behind, then will accelerate the pedal loosen to open very quickly, car can rise to block immediately, launch like this the machine voice is small, comfortable good.The another characteristics of the D is a compulsory low blocking, easy to high speed the hour overtakes a car, will accelerate quickly in of D drove the pedal trample after all, connect the compulsory low fend off the pass and then can reduce to block automatically, the car accelerates very quickly, after overtaking a car loosen to open the pedal of acceleration to can rise to block automatically again.The usage of the S, of L low the usage that blockThe automatic gearbox in in is placed in the low blocking the scope on of S or of Ls, can usage under an etc. circumstance.It change to can make use of to launch well into of S or of Ls the mechanism move, avoiding the car wheel system move the machine over hot, cause the system move the effect descent while going down slope.But change into from the of D of S or of L, car soon can't higher than rise to block the car homologously soon, otherwise strong vibration in opportunity to launch, make gearbox oil hoicked, even will damage the gearbox.The is another at rain fog weather hour, if the road adheres to the term bad, can change into a position for or of L, fixing at somely first lowly blocking driving, doing not use can automatically changing blocking, in order to prevent the car beats slippery.Must keep firmly in mind at the same time, beat the slippery hour can will choose to block the pole pushes into a motive for, cutting off launching machine, toing guarantee a car the safety.汽车变速器设计----------外文翻译我们知道，汽车发动机在一定的转速下能够达到最好的状态，此时发出的功率比较大，燃油经济性也比较好。

中英文翻译外文翻译THE RESEARCHS OFAMT SHIFTING SCHEDULESVehicular Automatic Transmission can be divided into three types: Automatic Transmission (AT), Automated Mechanical Transmission (AMT) and Continuously Variable Transmission (CVT). AMT has become a kind of transmission that is full of potentiality, due to its high transfer efficiency, low cost and easiness to manufacture.The research on AMT shifting performance is key technology in the developing. Shifting performance directly influence the market competition and industrialization of AMT.AMT has good market expectation, but during the shifting procedure, the power must be cut off which causes the poor shifting performance than AT and CVT. Only through improving the shifting performance can the commercial competence be established. So the virtual important thing is to find the way to improve shifting performance.The development of AMT can be divided into three phases: semi-automatic, automatic and intelligent. The two major part of AMT are: the hardware including the mastered object, executor, sensors and TCU; and the software performing the control strategy.The performance of AT shift influences greatly the performance of the vehicle. So the research on at shift quality is an important problem in the domain of AT researching. Shift quality control of AT is accomplished by electronic andhydraulic system. To shift smoothly, according the real time throttle valve opening and vehicle speed signal, the controller sends electronic signals to control oil pressure changing curve of the applying elements. this paper analyzes and research detailed shift quality control system，the analyzing model of shifting process and pressure changing curve of the applying elements Firstly this paper summarizes the existing evaluated quota of shift quality, and fully analyzes and introduces the existing control manner of AT shift quality.To meet the needs of research of vehicle starting and the real time control of shift, this paper puts forward a simplified model of engine-torque and a dynamics model of AT shifting process. Through the applying of the established model, this paper fully analyzes the process of the AT shifting.This paper drafts the proper oil pressure changing curve of the applying elements which can improve the AT shift quality, and gives the material calculated methods of the AG4 AT. This paper simulates the AG4 AT’s shifting process of 2H to 3H.The results of the simulation validate the established simplified models and the expected oil pressure changing curve.This paper fully analyzes the mechanism of the pressure regulating and flow controlling system of the AG4 AT, and preparatory discusses the design of the block-diagram of the shift quality control. This paper test the control system and hydraulic system of the AG4 AT by the AT hydraulic-electronic testing-bed. The result of the test validates the correction of these analyses.Automated Mechanical Transmission, as so called AMT, is a new-style transmission system. AMT technology applies the automatic technology to the manual mechanical transmission and makes the selection-gear, shift, clutch and throttle implement automatically. AMT technology is suitable for the situation of our country, and has an expansive market and development foreground. Shift schedules decide the time to shift and are the soul of the AMT. When the AMT is working, by comparing the states of the vehicle with the optimal shift schedules, the AMT decides the optimal shift time and achieves the shift automatically. This will lessen the tiredness of the driver and improve the safety. At the same time, the power and fuel-economy of the vehicle can also be improved. Theauthor chooses the shift schedule as the key technology problem to be researched and the main study aim of this thesis is to get the optimal shift schedules for the AMT and so improve the power and fuel-economy of the vehicle. Through analyzing the influence factors of power and fuel-economy for the automobile, the author get the establishment methods for the optimal-power shift schedule and optimal fuel-economy shift schedule. In order to solve the influence of mass on the shift schedule, the author presents a variable-structure-controlled shift system. This enriches the theory of shift schedules. Because the computer simulation can save a lot of manpower and material resources comparing with the true-car test, so in this thesis, the author uses the simulation toolbox MATLAB/Simulate to setup the simulation model for shift schedules. Using this model, the optimal-power shift schedule and optimal fuel-economy shift schedule above are simulated and proved to be reasonable.Shifting performance is defined as the extent of swiftness and softness during the procedure of non-power shifting and to extend the life of the power train. The index is comfort of passenger, time duration and shock, nine factors maybe influence the shifting performance, and two experimental methods can be used to investigate the nature of this performance: one is collecting real-time data during road experiment and analyzing them, the other is the simulation of the operation conditions of the vehicle.The core of the AMT system is the control strategy, the principle of the clutch engagement, shifting procedure, the choice of control method and the CAN communication between TCU and ECU can influence the shifting performance.Shifting schedule is the schedule of auto shifting time between two shifts with controlling parameters. It includes economical and dynamical shifting schedule. At present, shifting schedule of two controlling parameters (vehicle speed and opening on throttle) is mainly used. If shifting schedule is not good, shifting will not happen at right time and the working condition of engine will be severe. It will make the sound of engine abnormally and stability badly through the whole shifting procession. Sometimes even flame out Schedule of clutchengagement is determined by releasing journey of clutch, opening of throttle, shifting, vehicle speed and loading. The mainControlling goals are engaging quantity and engaging speed. The engaging control of clutch is mainly referred to the control of engaging speed. It is divided into three stages: fast, slow, fast. Shifting quality is directly influenced by the second stage. If engaging harder, it will make shifting concussion, even flame out; if engaging more slowly, it will make the friction time longer and reduce its longevity. The main controlling parameters are difference between initiative and passive and torques on both sides. When torques being approximately equal, it is proved by experiments that it can guarantee shifting time and not make concussion through the procession of engagement at the time of difference of rotating speed below some value. Meanwhile, the abrasion of clutch is not severe.Shifting procedure is the procedure through working harmoniously among engine, clutch and transmission. Their cooperation will affect shifting time heavily. In order to decrease the shifting time, the time that is spent on the friction of the clutch should be decreased first. If we intend to increase the time of non-load stage, which helps to minimize the difference of the rotary speed between the driving disc and the driven disc. If we intend to shorten the time of the non-load stage, engage the clutch immediately after the gear change. The clutch can engage in a satisfying period if the new method of controlling the engaging speed of the clutch is realizable. And the time that is spent on synchronizing the gears should also be shortened. It can be realized in the following two ways. The first is to decrease the difference of the driving gear and the driven gear. The second is to increase the shifting force. If realizing the union control between ECU and TCU by CAN bus, AMT has the best control and the best shifting performance by use of communication strategy between TCU and ECU.Influence on shifting performance by hardwareThe elements in hardware system are the basis of proper functions of AMT. Executors, sensors, electronic components, hydraulic systems have influences onshifting performance, the choice of hardware parameters is of vital important to improvement of shifting performance.With the development of the theory and technology of vehicle, the technical increasingly mature of microprocessor and the extensive application of electronic technique on the car, people have no limit at satisfying the automotive means of transportation only, facing gradually from the request of the car power, economy and easily manipulating, flexibility, safety, an d the intelligent type of car becomes the focus in the vision of people increasingly. Company’s publicity slogan of" person, car, life"," make people the center" etc. On the side exhibit the expectation of people to the automotive individuation, humanity.In the development direction of the car intelligence, the intelligence of the automatic gearbox has important effect. But the intelligence of the automatic gearbox embodies at the establishment of the shift regulation. For the fashion, for satisfying people to the new automotive request, for competitive advantage of the car type, at present, each big factory in world worked very much in shift regulation of new car type. Among those, the most arresting is AL4 automatic gearbox developed by PEUGEOT/CITROEN and RENAULT in that there unexpectedly are the 10 kinds of so many shift regulations. In the big system of person— car — road, the good and bad of the car control, reflect primarily in the coordination of the vehicle and environment (road), the coordination of the vehicle and person. And so, the electronic automatic control system can save various regulations to provide the driver to choose to use, not only having the economic regulation, motive (call to sport the type again) regulation, but also still having the general (usual) regulation, environment temperature and regulation with the outsider condition variety etc. Namely, the point of shifting can be freely enacted for every kind of regulation. In the intelligence direction of the shift regulation, everyone has made much work up to now, parts of the results has been applied on the car. But the work that developing this intelligent shift regulation still is hard, this is mainly because of:1. The intelligence degree of the current intelligent gearbox needs to be increased, and it expresses at that accurate degree to identify environment is nothigh and to identify the driver’s driving can't give satisfaction.2. The intelligence function is still not perfect. The intelligent automatically shift system is an open system; it must be continuously perfect and plentiful on the current foundation. Only this way, it can adapt to the driving request of the different drivers, reducing the driver’s labor strength, increasing the performance of the whole vehicle.Conventional design method which used in the structure parameters' design of automobile gear box and synchronizer is a time-wasting job and hard work, and it is difficult to get idea design parameters and no good to the enhancement of products qualities. The optimum design of automobile gearbox and synchronizer which take the advantage of computers seeking the best structure parameters within constrains is a perfect and high-quality design method. The main target of this article is to set up a optimum mathematical model of structure parameters of the truck's gearbox and synchronizer, the auth or use a optimum method based on K-T equation to improve the design level of automobile gearbox and synchronizer. Gear box is a important part of transmission, so the optimization of automobile gearbox is very important because the transmission is a main part of automobile. According to the design request and character sofa sort of truck, the optimum mathematical model of truck's gearbox is analyzed and set up in this article to decrease its weight and volume when the strength, stiffness, and lifetime of parts are permitted. And we can receive a satisfaction result through optimizing it's parameter for instance.Synchronizer is a important part of automobile gearbox, it make drive gear and driven gear engaged after their synchronized, so it can decrease engaged shock and noise, it can decrease shift forcing and make it comfort to gear shift and increase the life of synchronizer. The synchronized process of synchronizer is analyzed in this article; we can receive a satisfaction result through optimizing its influence parameter for instance when the synchronized time is the shortest. The optimum toolbox of MATLAB is a convenient of ware of modern optimization with fast speed and powerful function. The algorithms of different mathematical subsets are divided into different librarians in the form offunctions in MATLAB optimum toolbox. When we use them, we just call the functions and give special parameters to solve the problems and this will be fast and accurate. The author gives an optimum design for automobile gearbox and synchronizer by using the optimum toolbox of MATLAB and receives a satisfaction result.自动变速器换档规律的研究车辆自动变速器通常分为液力机械式自动变速器（简称AT）、电控机械式自动变速器（简称AMT）和机械式无级变速器（简称CVT）。

机械原理课程设计7档双离合自动变速器结构研究与设计姓名：孔令兴学号：20091096班级：车辆09级4班指导教师：陈奇合肥工业大学机械与汽车工程学院2012年5月目录概述 (3)第一章双离合自动变速器简介 (5)1.1 传统变速器以及其他新兴自动变速器存在的问题 (5)1.2 DCT自动变速器的结构与工作原理 (6)一、DCT自动变速器的结构 (6)二、DCT变速器的工作原理 (9)1.3 DCT双离合自动变速器的工作特点 (11)第一章双离合变速器的传动路线的设计 (12)2.1 传动轴的设计 (12)2.2 各档传动路线的设计 (13)第三章传动装置几何参数的确定 (17)3.1 各档位传动比的确定 (17)（一）、最大传动比的确定 (17)（二）、最小传动比的确定 (18)（三）、其他各档位传动比的设计计算 (19)3.2 传动齿轮参数的确定 (19)（一）、中心距的设计 (19)（二）齿轮结构特征参数的设计 (20)（三）、各档齿轮齿数分配 (22)总结 (27)参考文献 (28)概述变速器是汽车的关键部件。

随着消费者对汽车动力性、经济性的越来越高的要求，研发动力性能好、机械效率高、操作方便的变速箱已经成为各大汽车厂家的重要工作。

近年来，自动变速器（AT）、手自一体变速器（AMT）、机械式无级变速器（CVT）以及双离合式自动变速器的研究和应用都取得了极大的进步，带来了巨大的经济效益。

双离合器式自动变速器( DCT ) 除具有自动变速器起步和换挡品质优良、实现自动变速的特点外, 还具有手动变速器( MT ) 传动效率高、安装空间紧凑、质量轻、制造成本低等诸多优点, 产品加工制造过程对MT具有良好的工艺继承性, 发展应用前景良好, 是现有量产配套的各类变速器的有效替代产品。

目前, DCT 虽主要用于轿车, 但就其工作原理而言,亦可以应用于大、中型车辆及工程机械、自走式农业机械等其他非道路车辆, 应用范围较广。

变速箱在我国工程机械主要核心元部件中，唯有传动元部件国内配套体系最完善，市场满足率也最高，且也是最具自主知识产权的关键配套件。

国产核心元部件之一的液压元件，从价值上讲，国产配套满足率只有30%，特别是价值很高的变量液压元件，几乎全依赖进口。

而传动核心元部件的国产配套件的满足率在70%～75%以上，只有少数高档传动元部件及大规格传动元部件仍需进口。

在变速箱方面，世界上一直是两大流派，一种是像德国采埃孚和美国德纳那样的定轴式箱，另一种就像目前我国用得最多的及卡特、小松等所用的行星式变速箱。

行星式变速箱中，像我国目前的只有两个行星排，叫简单行星式，制造、维护相对比较容易一些。

另一种像卡特、小松等复杂行星式，制造工艺比较复杂。

这两种流派各有优劣，因此两大流派一直在世界上并存。

但对中国的实际情况，复杂行星式制造难度更大，川齿引进卡特技术，最终未形成产品就是一个例子。

老的简单行星式变速箱，虽然目前仍在最广泛地使用，但由于某些缺陷已从根本上无法克服，技术也再无突破性发展。

因此变速箱在整个行业的技术发展中，瞄准了世界一流水平的采埃孚箱。

既有杭齿引进采埃孚技术基础，又有柳工与采埃孚合资的技术基础，同时又有广泛地使用、维护及配件基础。

另外与其配套的冲压焊接式变矩器已在陕西航天动力开发成功，并已大批量配套。

因此中国目前新型双变技术主流方向，已正在向采埃孚型方向发展。

主要配套件企业杭齿所生产的高水平采埃孚双变已批量推向了市场，并从装载机变速箱经过变型设计已发展到压路机、平地机等多种工程机械产品上。

主机企业柳工、龙工、厦工、成工等，都已不同程度地研发出或正在研发该系列变速箱。

并已从3t型、5t型到6t型,已逐步开始形成了中等型号系列新型双变系统。

该双变的关键技术是微电脑控制的电液控制系统。

其中最关键的核心部份是微处理器及电液控制阀。

目前中国国内攻下这两项关键核心技术已到了最后攻坚阶段。

一旦这些核心技术完全攻克，我国新一代换代双变技术将会很快得到广泛实现。

毕业设计（论文）外文文献翻译文献、资料中文题目：汽车变速器设计文献、资料英文题目：Transmission design文献、资料来源：文献、资料发表（出版）日期：院（部）：专业：机械设计制造及其自动化班级：姓名：学号：指导教师：翻译日期： 2017.02.14毕业论文（设计）外文文献翻译汽车变速器设计我们知道，汽车发动机在一定的转速下能够达到最好的状态，此时发出的功率比较大，燃油经济性也比较好。

因此，我们希望发动机总是在最好的状态下工作。

但是，汽车在使用的时候需要有不同的速度，这样就产生了矛盾。

这个矛盾要通过变速器来解决。

汽车变速器的作用用一句话概括，就叫做变速变扭，即增速减扭或减速增扭。

为什么减速可以增扭，而增速又要减扭矩呢？设发动机输出的功率不变，功率可以表示为N=wT，其中w是转动的角速度，T是扭矩。

当N固定的时候，w与T是成反比的。

所以增速必减扭矩，减速必增扭矩。

汽车变速器齿轮传动就根据变速变扭的原理，分成各个档位对应不同的传动比，以适应不同的运行状况。

一般的手动变速器内设置输入轴、中间轴和输出轴，又称三轴式，另外还有倒档轴。

三轴式是变速器的主体结构，输入轴的转速也就是发动机的转速，输出轴转速则是中间轴与输出轴之间不同齿轮啮合所产生的转速。

不同的齿轮啮合就有不同的传动比，也就有了不同的转速。

例如郑州日产ZN6481W2G型SUV车手动变速器，它的传动比分别是：1档3.704:1；2档2.202:1；3档1.414:1；4档1:1；5档（超速档）0.802:1。

当汽车启动司机选择1档时，拨叉将1/2档同步器向后接合1档齿轮并将它锁定输出轴上，动力经输入轴、中间轴和输出轴上的1档齿轮，1档齿轮带动输出轴，输出轴将动力传递到传动轴上（红色箭头）。

典型1档变速齿轮传动比是3:1,也就是说输入轴转3圈，输出轴转1圈。

当汽车增速司机选择2档时，拨叉将1/2档同步器与1档分离后接合2档齿轮并锁定输出轴上，动力传递路线相似，所不同的是输出轴上的1档齿轮换成2档齿轮带动输出轴。

外文原文：TransmissionsTransmissions have to compromise on either ride comfort or efficiency, but a new approach to the dog engagement gearbox could improve both.With tightening emissions regulations, carmakers are not just confining their efforts to improving combustion and after-treatment. Many are finding that modern engines are so advanced that the benefits of some engine technologies are small compared to the huge development costs involved.It's important to look at the whole vehicle in order to improve emissions. As the second most expensive piece of kit in the car, the transmission is the logical next place to look.Of all transmission technologies, the manual gearbox is the most efficient; around 96percent of the energy that is put in comes out of the other end. But not everyone can drive one or wants to. Because you have to dip the clutch pedal, it's less comfortable to drive in heavy traffic. It makes the driver tired and the torque interruptions' head-nod effect on passengers can be wearing.The driver's clutch control and corresponding torque interruptions are also the manual's weak point. When accelerating up through the gearbox, each up-shift requires the driver to cut the torque momentarily by lifting the gas pedal and dipping the clutch. It may just take a second to complete the operation, but during this time the vehicle is losing speed and acceleration.At the opposite and of the spectrum is the traditional automatic. Its shift quality is good thanks to its torque converter, but efficiency is relatively poor despite recent advances. Because of this ,a lot of the current research is trying to find an efficient alternative to the conventional automatic.The main technologies are continuously variable transmissions (CVTs); dual clutch transmissions(DCTs) and automated manual transmissions(AMTs).They all offer different benefits over the conventional planetary automatic.The CVT uses a belt chain or toroidal shaped dish drive to vary an infinite number of gear ratios. It has improved efficiency and cost when compared to conventional automatics.Its advantage comes from its simplicitu. It consists of very few components; usually a rubber or metal-link belt; a hydraulically operated driving pulley, a mechanical torque-sensing driving pulley, microprocessors and some sensors.The transmissions works by varying the distance between the faces of the two main pulleys.The pulleys have V-shaped grooves in which the connecting belt rides. One side of the pulley is fixed axially; the other side moves, actuated by hydraulics.When actuatec, the cylinder can increase or reduce the amount of space between the two sides of the pulley. This allows the belt to ride lower or higher along the walls ofthe pulley, depending on driving conditions. This changes the gear ratio. A torodial-type design works in a similar way but runs on discs and power-rollers.The "stepless" nature of its design is CVT's biggest draw for automotive engineers. Because of this, a CVT can work to keep the engine in its optimum power range, thereby increasing efficiency and mileage. A CVT can convert every point on the engine's operating curve to a corresponding point on its own operating curve.The transmission is most popular with Japanese carmakers and Japanese supplier JATCO is a major producer. But in the US and Europe driving styles are different. Uptake has been slow despite Audi and other manufacturers having offered CVT otions on their ranges.The DCT is, in effect, two manual gearboxes coupled together. Gear shifts are made by switching from one clutch on one gearbox to another clutch on the other. The shift quality is equal to a conventional automatic, but slip, fluid drag and lydraulic losses in the system result in only slightly improved efficiency and acceleration over the conventional planetary automatic. Developing the control strategy is costly too."Recent advances in conventional automatic technology have weakened the argument to develop and set up production for CVT or DCT." says Bill Martin, managing director of transmission firm zeroshift. "Some carmakers have cancelled DCT projects because of the cost."The cheapest way to build an automatic is with an AMT. AMTs use actuators to replace the clutch pedal and gear stick of a conventional manual. They keep the high efficiency and acceleration of a manual gearbox, but the shift quality on some models is lacking. Torque interruptions and the head-nod effect are the most common complaint.so what is the alternative? There are always new ideas in transmissions, but Zeroshift says that its technology has efficiency benefits over a manual, delivering fuel economy improvements to city driving. Shift quality can also be equal to that of a refined automatic.Zeroshift's approach is an upgrade to the AMT. The synchromesh is replaced with an advanced dog enqaqement system.Dog engagement has been used for many years in motor sport to allow fast shifts. Conventional dog boxes are unsuitable for road use as the large spaces between the drive lugs or "dogs" create backlash, an uncomfortable shunt caused by the sudden change in torque direction.Zeroshift's technology solves this problem by adding a second set of drive dogs. It has also made each of the two sets of dogs only capable of transmitting torque in one or other opposing directions. "By controlling the engagement and disengagement of the two sets you can shift into the new gear befor disengaging the previous gear, "says Martin. "The shift quality is smoother than a typical modern six-speed automatic luxury car."The shift is instant and the torque is not interrupted.This philosophy is used for both up and down shifts."In conventional AMT there is an emissions spike during a shift due to the need to back off and reintroduce throttle, this is eliminated by going seamless, "says Martin. "This also reduces fuel consumption."It is a relative newcomer to the transmission sector, but the firm says that it is already attracting the attention of major European and US carmakers. The big draw is as a low-cost alternative to DCT, says Martin.Because the manual gearbox architecture is largely maintained, production costs and complexity are not greater than for a conventional AMT. Development of the controls side is also considerably cheaper. Music to the ears of engineers trying to cut emissions and costs."Most of the carmakers have seen the system at least once," says Martion. "Some signed us immediately. Some have said not yet. None have said no. "That may be the clearest sign yet that when it comes to powertrain developments, carmakers are starting to focus on the transmission.HOW ZWROSHIFT WORKSThe hardware consists of two sets of bullets. mounted and actuated on two independent bullet rings. both sets of bullets run on the common hub, which is attached to the shaft with splines.Each bullet has a special profile. On one side they have an angled face for engagement. These are diagonally opposed, allowing the bullet to have a drive function for one gear and an overrun function for the other gear. The engagement faces taper backwards slightly to ensure the bullet latches onto the engaged gear under load.the opposite corners have a ramp, which pushes the bullet out of the previous gear once the new gear has been engaged.In neutral both bullet rings are positioned midway between the ratios. To select first gear, the bullets are moved into mesh with the engagement dogs.The bullets are actuated via shift forks conected to the shift actuators.The driving bullets lock first gear to the output shaft and transfer torque from the gearwheel onto the output shaft. The first gear overrun bullets are also moved into gear to lock the wheel to the output shaft in the opposite direction. This transfrs torque from the gearwheel onto the output shaft when the throttle closes and the engine overruns. This eliminates the backlash you'd expect from a dog engagement gearbox.To shift up with an open throttle, first gear's overrun bullets are unloaded and move in to engage second gear. This is followed by the previous driving ring which becomes unloaded when second gear is taken up.If the bullet is stopped from engaging fully-dog-face to dog-face-the second gear wheel opens an engagement window due to the relative speed difference. With the bullet pushed against the engagement dog compliance between the fork and actuator allows the stored energyto fire the bullet into the window.The first gear overrun bullets have now become the second gear drive bullets. As second gear takes over, the load is removed from the first gear drive bullets. These bullets are now no longer held by their retention angie and can be either moved out ofgear by actuators or pushed out of gear by contact with the ramp face of the bullet.The first gear drive bullets then move across into engagement with second gear. In second gear, the roles of the bullets are reversed.Audi RoadjetAudi plans to add comfort, luxury and practicality without increasing emissions The Roadjet concept, first shown at Detroit in January 2006,indicates a number of technical directions that Audi going to take in the coming year. The firm is focusing on interior design, powertrain, chassis, electronics and safety innovations.These new directions will help Audi strengthen its position in the sub-luxury market that it previously had to itself. Audi has two main tactics to attract new customers in the US. It is breaking into the sports utility vehicle(SUV)and compact utility vehicle(CUV)markets.It also introduces new luxury and lifestyle features to strengthen its position in the US; sales there still lag behind those of BMW, Lexus and Mercedes-Benz. The recently launched Q7 off-road luxury vehicle is a late bid to capitalise on the SUV boom.In Europe, the carmaker's technical innovations such as aluminium construction, four-wheel-drive, and novel powertrain technologies have been successful. But if Audi wants to increase its US market share, it needs to innovate in those areas valued by American customers: comfort, luxury and practicality.Audi's designers have focused on this in the interior. They have devised a new wrap-around instrument panel shape to replace the more functional design in existing models. They have expanded the vehicle's multi-media interface (MMI)control system, used for cruise control, suspension, climate and entertainment separate controls. Combined with an upgraded climate system, occupants can set their own individual climate settings.Soft, warm, earthy colours are used in the Roadjet to create a feeling of well-being. The concept uses high quality functional materials: the upholstery is fine leather; the floor is neoprene. The space between the rear seats can house a range of optional equipment: the show car featured an espresso coffee machine. Storage boxes and baby carriers are more realistic alternatives.To enhance practicality, the rear seats slide backwards and forwards diagonally to increase shoulder and leg-room or rear load space. When the rear seats are in their most forward position, an oblique-facing child seat can be used behind the seats.Roadjet's load bay features an eletrically extending load floor to ease loading, offering unmerous lashing points to secure luggage items. The sliding seats and extending load floor are very likely to enter production on Audi's Q5 and A4 models.To heighten the sense of luxury, the concept uses a costly 1,000W Bang & Olufsen sound system with 14-speakers.This incorporates a "digital voice support" function that uses microphones and the car's speakers to pick up and amplify passengers' voices to ensure clear conversation even at high speeds.In a bid to improve road safety, convenience and traffic management, carmakers are working to common standards to develop a new in-car system to talk to other cars androadside wireless olcal area networks. In traffic jams, bad weather or accident situations, cars send information to emergency services, other cars and traffic computers. The Roadjet concept featres previews such a system.The weight of all the new electronics and luxury equipment in this segment, combined with customers' growing demand for power is having a negative effect on exhaust emissions and fuel consumption. Audi is looking at sophisticated technical solutions to balance the equation.Roadjet's 3.2-litre gasoline direct injection engine is based on an existing engine but features a new fixed intake manifold with an integral vacuum reservoir to increase its output. This is combined with a two-stage cam operated variable valve lit technology to increase output.Despite the sports car performance, the Roadjet's overall fuel consumption is slightly lower than the current A4 Quattro 3.2FSI.The valve train technology, due to enter production later in 2006,lets the engine perform economically and smoothly during normal driving, switching automatically to more responsive, more powerful characteristics when the driver demands.Roadjet also has the first Audi application of speeddependent variable ratio dynamic steering for a stable highspeed motorway ride but with enhanced control on twisty country roads. Electronically-controlled variable rate dampers automatically adjust from soft and comfortable to firm and sporty to enhance safety and handling.Audi's engineers have electronically linked all of these systems to create three driver-selectable programmes: dynamic, comfort and sport. Each programme adjusts the dampers, steering, gearbox and engine eletronics to give different driving experiences.Roadjet's body styling marks a new direction for the carmaker.At 1.55m high with a wheelbase 4.7m long and 2.85m wide, the concept is roomy. The firm has used a combination of sharp feature lines and careully-sculpted concave-section doors to disguise the height. While the trademark LED tail lights are likely to enter production unchanged, steerable xenon gas discharge lights will replace the LEDs in the headlamps.Around the end of 2007 Audi will launch the Q5 CUV, based on the next A4 platform. Smaller and lighter than the Q7,it will be well placed to compete in the profitable CUV segment in the US. The Roadjet previews elements of the interior and exterior styling of this model.The Q5 will need to be more rugged to match the outdoor lifestyle image of the CUVsegment. At the same time, for the European market, the Roadjet's sharp style previews the next A4 model range, which may produce a new hatchback body in 2007 to join the conventional saloon and Avant estate. The dashboard and other new interior refinements are likely to spread across the rest of the Audi range over the next 24 months.中文译文：变速器变速箱通常不得不在舒适性和效率之间做出选择，但一种新型的“犬牙啮合式”变速箱可以同时改善这两种性能。