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发表于 30-5-2011 17:41:01
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回复 chenda125 的帖子
AUTOMATIC TRANSMISSION OUTLINE?
Vehicle with the automatic transmission took one kind of new clutch, was most early by 1939 an general company Austria this not Bill development, at present already has experienced more than half century development, moreover its form also many and varied.In 1977 American gram vegetable Si forced the company first to develop the belt to lock the coupling the fluid strength bending moment.This kind locks the installment in fact is the completely automatic coupling.When locks the coupling, the bending moment will not have an effect.This to improves the fuel the efficiency and reduces the transmission gearbox the temperature to have the profit. On the modern passenger vehicle, common uses the electrically controlled hydraulic automatic transmission gearbox, mainly is two major part is composed by the automatic clutch and the automatic transmission.It can act according to the accelerator the opening and the vehicle speed change, carries on automatically shifts gears.Compares with the variator, the hydraulic automatic transmission gearbox biggest difference is in the structure, it is by the hydraulic control gear changing system constitution.Therefore, the hydraulic automatic transmission gearbox is not the true stepless speed change, has the files position.Between its can realize is in two keeps off the stepless speed change.But the variator is two group of speed change wheel disk and a transmission belt composes, therefore, it the automatic transmission structure the tradition to be simpler than, the volume is smaller.Moreover, it may change the velocity ratio freely, thus realizes the entire journey stepless speed change, causes the automobile the vehicle speed change to be steady, the variator stepless speed change principle key, is two drive pulleys and joins this two pulleys the transmission belt, each pulley all synthesizes V shape trough by pair of each other the cone to be composed, joins two pulleys through the transmission belt, moves the cone using the hydraulic control organization opening and closing, causes the transmission belt to change to the pulley axle center radial direction position, thus obtains between two pulleys the velocity ratios (the most wide range to be possible to reach generally 5:1).Although the automatic transmission keeps off can expand the self-shifting transmission the scope, but it by no means safe rapid, between the having steps speed change and the stepless speed change, the ideal variator is only in the entire transmission scope internal energy continual, not keeps off compared to the cut gear ratio, causes the transmission gearbox according to best to shift gears throughout the rule self-shifting transmission.Stepless is to the automatic transmission ideal pursue.
1．The modern variator transmission efficiency enhances, the accelerator responded quick, the oil consumption is low, along with the automobile technology progress, already more and more did not satisfy the hydraulic automatic transmission gearbox, hoped improved the variator thoroughly, from realized the automobile from the having steps speed change stage to the stepless speed change stage leap.Ford, the Philippine Asia, enterprises and so on Audi in abundance promoted especially have been able to match the great displacement engine the variator.At present the domestic automatic files basically all are the hydraulic automatic transmission gearbox, only then Audi has used the variator.The Audi stepless/manual integration transmission gearbox, it in the original variator foundation, carries on in many technical the innovation, the improvement and the enhancement.The limitless speed change equipment has the automatic control device, in the driving may act according to the vehicle speed automatic control files position, does not need the manual control, omits many shifts gears and treads steps on the meeting and parting the work. ?
?2.Automatic transmission textural classification Common vehicles may divide into the manual transmission gearbox and the automatic transmission two big kinds with the transmission gearbox.The automatic transmission is does not refer according to human's hand power, but can realize automatically shifts gears the function transmission gearbox.At present on the automobile the commonly used automatic transmission type includes: Hydraulic automatic transmission gearbox, hydraulic transmission automatic transmission, electric drive automatic transmission, having steps type machinery automatic transmission and stepless -like machinery automatic transmission and so on. ? ?
The automatic transmission according to the automobile drive type difference, may divide into after actuates the automatic transmission and first actuates the automatic transmission namely automatic driving axle.Latter actuates the automatic transmission the bending moment and the gear transmission gearbox input axis and the output shaft on the identical spool thread about, the engine power after the bending moment, the transmission gearbox, the drive shaft, the driving axle main gear box, the differential device and the rear axle passes to two trailing wheels. Front actuates the automatic transmission also to be loaded with the main gear box and the differential device in the automatic transmission shell.Vertical sets at in front of the engine to actuate the transmission gearbox the structure and the arrangement with latter actuates the automatic transmission basic same; In front of the horizontal engine actuates the transmission gearbox as a result of the automobile crosswise size limit, the request to have the small axial size, usually designs the input axis and the output shaft two spool threads the way, the bending moment and the gear transmission gearbox input axis arrangement in the place above, the output shaft arrangement in underneath, reduced the transmission gearbox overall axial size, but increased its altitude. The automatic transmission keeps off the figure according to the forward gears to be different, may divide into 2 forward gears, 3 forward gears, 4 forward gears, 5 forward gears.The new passenger vehicle installs with the automatic transmission basically all is 4 forward gears, does not have the overdrive transmission.At present oneself after develops is loaded with 5 forward gears automatic transmission passenger vehicle.
3．The variator is the automatic transmission one kind of manual transmission gearbox, the structure simple, accurate effective, but, also has the operation complex, the long-term use easy weary, shifts gears when attacks and so on the deficiencies in a big way.The automatic files (called limitless speed change) equips has the automatic control device, in the driving may act according to the vehicle speed automatic control files position, does not need the manual control, omitted many shifted gears and treads steps on the meeting and parting the work. The variator may (either rotational speed) transforms steadily from one kind of torque into another kind of torque (or rotational speed), (as soon as is not step by step or keeps off) in the change process the jump, but is stable, relaxes changes gradually.The variator has the fluid strength type variator (also to call fluid strength torque converter) and the mechanical variator and so on two kinds.the electrically controlled automatic transmission mainly by the fluid strength bending moment, the planetary gears, the hydraulic control system and the electrically controlled system four major part is composed. The mechanical variator may divide into the impact type and the friction type two kinds according to its function.The impact type is one off and on transmission, namely the beat -like, the structure is extremely complex, also when work must have the very big impact load, applied on the automobile Shang You very many difficulties.But behind the friction type is one continual transmission, the engine turns the system of forces to pass to uniform taking advantage of the friction torque change along the place, its structure quite is simple, at present already applied on the automobile.3. automatic transmission characteristic.Automatic transmissions can carry on the complicated acceleration, decelerate the transmission gearbox to shift gears and so on the functions, has the speed change smoothly, driving facile and so on the merits.The automobile automatic transmission general and the bending moment uses together, has the fluid drive characteristic, may make up the mechanical variable speed drive some shortcomings.It may act according to the engine the operating mode and the vehicle speed situation, the automatic selection keeps off the position, moreover has the following remarkable characteristic:(1) Entire vehicle has the better driving performance. (2) Good driving quality: Not only the automatic speed-varied gear keeps off the position transformation quickly moreover steadily, enhanced the automobile riding comfortableness. (3) High driving security: In the vehicles travel process, the pilot must act according to the path, the traffic conditions change, carries on the change and the adjustment to the vehicles travel direction and the speed. (4) reduces the exhaust gas discharge: Engine when idling regime and high speed movement, in the emissions waste gas, CO or the CH compound density is high, but the automatic transmission application, may cause the engine to be in the economical rotational speed region to revolve frequently, also is works in the small pollution emissions rotational speed scope, thus reduced the exhaust pollution. (5) may lengthen the engine and the power transmission service life: Because the automatic transmission uses the fluid strength bending moment and the engine “the elasticity” the connection, the outside impact load may through the pale pinkish purple cushion, have the over-load protection function.Shifts gears, the brake when the automobile start could the absorbed oscillation, reduce the engine and the power transmission correspondingly moves the load.(6) Operation is simple: Only must establish the hydraulic pressure working valve the position, the automatic transmission might according to need to carry on automatic Canada to keep off and to reduce keeps off, omits started and shifts gears when has trod the coupling, the replacement gearshift lever position and the relaxation accelerator and so on the complex working instruction, reduced pilot's labor intensity greatly. (7) Enhanced the automobile smoothness: Because uses the fluid strength bending moment starts when the automobile, on the wheel force of traction gradually increases, does not have vibrates and reduces the wheel glide, causes the start easily steady.The automobile also may fall to lowly in travel stable vehicle speed, even is the zero.When the running resistance increases, the engine cannot appear the flameout. (8) Enhances the productivity: Shifts gears when power basic not interrupted, may guarantee the automobile has the good acceleration time and the high average vehicle speed, causes the engine the attrition reduction, lengthened the overhaul gap course, enhanced dispatched a vehicle rate. But the automatic transmission shortcoming is: Compares with the manual transmission gearbox, its structure is complex, the components processing difficulty is big, the production cost is high, the repair is also troublesome.Moreover the automatic transmission transmission efficiency insufficiently is high, certainly, through optimizes, the fluid strength bending moment with the engine match locks, the increase keeps off measures and so on figure, may cause the automatic transmission the transmission efficiency efficiency close manual transmission gearbox level.4.
4．Automatic transmission application form ? ? Modern vehicles with the automatic transmission application, mainly have following two forms:
(1) hydraulic control type automatic transmission: Between this is one kind treads using the vehicle speed and the accelerator pedal inputs the velocity ratio which the relations decided, carries on the automatic control through the flowing tubing head pressure control mechanism the transmission gearbox.Commonly used hydraulic control type automatic transmission generally of fluid strength pale pinkish purple or bending moment, hydraulic control system and planetary transmission system composition.
In the work the pilot treads the accelerator the position or the engine air feeder vacuum degree and the automobile moving velocity, can direct the hydraulic control system work, the hydraulic control system use liquid head control planet gear system coupling and the brake, and changes the planetary transmission the condition.Above process is completely carries on in the transmission gearbox interior, does not need pilot's operation, namely so-called shifts gears automatically.In here fluid strength bending moment function is: Increases the automobile start the torque to enhance the vehicles the start performance, may reduce the speed change impact, the room partition engine output torque vibration, but has the input axis and the output shaft flowing idle operation actually slips causes the question which the engine power loses, thus in after that introduced has locked the organization, although has solved some problems, but because is controlled respectively the part the restriction, the bending moment function fully displayed with difficulty, specially reduced the motor torque change the question also to need to solve.Moreover this kind locks the coupling only to be able to change in the small high speed scope in the motor torque to have an effect, therefore cannot enhance the fuel oil fully the efficiency, for solves this problem, in the world each big car company has taken all sorts of measures, if uses locks the coupling micro glide way; Uses the coherent junction box absorbed oscillation the way and so on, but the effect is not very ideal, afterwards people electronic technology introduction automobile domain, therefore took one kind of new automatic transmission, the electronic control type automatic transmission arises at the historic moment.
(2) Electronic control type automatic transmission: In the conventional automobile automatic transmission locks the type bending moment * hydraulic transmission, but along with the electronic technology on the automobile promoted application, uses installments and so on miniature electronic accounting machine to take the automatic transmission the hydraulic control installment, uses certain hydraulic control installment to shift gears again the organization to the transmission gearbox to carry on the operation control, not only like this causes the shifting gears time to be more precise, to shift gears steadily, moreover operates freely nimbly; On the other hand may cause the speed change to keep off unifies as far as possible with pilot's wish; Next uses the electronic control, suits travel condition through the choice the best velocity ratio, may enhance the automobile the power, enhances riding comfortableness, and unifies with the engine control, enhances the fuel oil correspondingly the efficiency. the electronic control type automatic transmission is uses the flowing tubing head pressure return route the magnet coil circular telegram and the power failure, controls the transmission gearbox the speed change fixed time and time the speed change transient characteristic.Its electronic control system mainly has: When speed change control, self-locking control, speed change when transient characteristic control, flowing tubing head pressure control, speed change locks the control and so on.In the electronic control type automatic transmission, transforms after the vehicle speed sensor and the throttle valve opening sensor the vehicle speed and the throttle valve opening the electrical signal, took electronic control ECU the input signal, after transmission gearbox in ECU computation processing, at the right moment the output signal gives the solenoid valve again, uses these solenoid valves to control the flowing tubing head pressure return route.Obviously, the hydraulic control type automatic transmission and the electronic control type automatic transmission similarity lies in, the use electronic technology examination way and to the flowing tubing head pressure in the control mode, the electronic control type automatic transmission is uses the sensor to examine the vehicle speed and the throttle valve opening, carries on the control using the electronic technology to the solenoid valve, thus realizes to the automobile automatic transmission carries on more rapid, at the right moment and more precise control.
5. Electrically controlled machinery stepless automatic transmission (CVT) mechanical type variator and the fluid drive automatic transmission compare, may compare favorably with in the operation conveniences and the riding comfortable aspect with the fluid strength bending moment, but its transmission efficiency far is higher than the fluid moment of force actually.Main is it can coordinate the vehicles outside travel condition and the engine loading well, displays the engine power fully, enhances the entire vehicle fuel oil efficiency.Theoretically speaking CVT may cause the engine to move throughout under the economical operating mode.Moreover, the CVT tractive quality is good, when pick-up does not need to shut off the power, can obviously enhance passes another vehicle the performance. The people very are early realize CVT are facilitate driving, enhance the vehicles fuel oil efficient ideal installment, appears the bipyramid ball, the plate, the hooped column body from several dozens years ago and so on develops the leather belt transmission, but as a result of the rubbing surface friction coefficient and the components withstanding unit pressure limit, adds in the processing craft and the control difficult problem, cannot transmit compares the high efficiency, only limits uses in on the compact car.In the 20th century 70's mid and late parts, CVT developed successfully and puts in the market in 1982. Ford Corporation in 1987 will install the steel belt in the world the CVT passenger vehicle to introduce the market for the first time, received the user high praise.At the same time some people thought steel belt generally all when five, movement each speed is different, has the friction and the attrition mutually.If a belt breaks, can initiate other belt sonchus asper to get down continually, therefore in 1956 Germany started the stepless chain drive research, has produced 20 many kinds of prototypes to 1987, the various countries regards it for the self-shifting transmission technology brand-new way.
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