1、The motor turning systemAlong with automobile electronic technology swift and violent development, the people also day by day enhance to the motor turning handling quality request. The motor turning system changed, the hydraulic pressure boost from the traditional machinery changes (Hydraulic Power

2、Steering, is called HPS, the electrically controlled hydraulic pressure boost changes (Elect ric Hydraulic Power Steering, is called EHPS, develops the electrically operated boost steering system (Elect ric Power Steering, is called EPS, finally also will transit to the line controls the steering sy

3、stem (Steer By Wire, will be called SBW.The machinery steering system is refers by pilot's physical strength achievement changes the energy, in which all power transmission all is mechanical, the automobile changes the movement is operates the steering wheel by the pilot, transmits through the d

4、iverter and a series of members changes the wheel to realize. The mechanical steering system by changes the control mechanism, the diverter and major part changes the gearing 3 to be composed.Usually may divide into according to the mechanical diverter form: The gear rack type, follows round the wor

5、ld -like, the worm bearing adjuster hoop type, the worm bearing adjuster refers sells the type. Is the gear rack type and follows using the broadest two kinds round the world -like (uses in needing time big steering force.In follows round the world -like in the diverter, the input changes the circle

6、 and the output steering arm pivot angle is proportional; In the gear rack type diverter, the input changes the turn and the output rack displacement is proportional. Follows round the world -like the diverter because is the rolling friction form, thus the transmission efficiency is very high, the e

7、ase of operation also the service life are long, moreover bearing capacity, therefore widely applies on the truck. The gear rack type diverter with follows round the world -like compares, the most major characteristic is the rigidity is big, the structure compact weight is light, also the cost is lo

8、w. Because this way passes on easily by the wheel the reacting force to thesteering wheel, therefore has to the pavement behavior response keen merit, but simultaneously also easy to have phenomena and so on goon and oscillation, also its load bearing efficiency relative weak, therefore mainly appli

9、es on the compact car and the pickup truck, at present the majority of low end passenger vehicle uses is the gear rack type machinery steering system.Along with the vehicles carrying capacity increase as well as the people to the vehicles handling quality request enhancement, the simple mechanical t

10、ype steering system were already unable to meet the needs, the power steering system arise at the historic moment, it could rotate the steering wheel while the pilot to provide the boost, the power steering system divides into the hydraulic pressure steering system and the electrically operated stee

11、ring system 2kinds.Hydraulic pressure steering system is at present uses the most widespread steering system.The hydraulic pressure steering system increased the hydraulic system in the mechanical system foundation, including hydraulic pump, V shape band pulley, drill tubing, feed installment, boost

12、 installment and control valve. It with the aid of in the motor car engine power actuation hydraulic pump, the air compressor and the generator and so on, by the fluid strength, the physical strength or the electric power increases the pilot to operate the strength which the front wheel changes, ena

13、bles the pilot to be possible nimbly to operate motor turning facilely, reduced the labor intensity, enhanced the travel security.The hydraulic pressure boost steering system from invented already had about half century history to the present, might say was one kind of more perfect system, because i

14、ts work reliable, the technology mature still widely is applied until now. It takes the power supply by the hydraulic pump, after oil pipe-line control valves to power hydraulic cylinder feed, through the connecting rod impetus rotation gear movement, may changes the boost through the change cylinde

15、r bore and the flowing tubing head pressure size the size, from this achieved changes the boost the function. The traditional hydraulic pressure type power steering system may divide into generally according to the liquid flow form: Ordinary flow type and atmosphericpressure type 2 kind of types, al

16、so may divide into according to the control valve form transfers the valve type and the slide-valve type.Along with hydraulic pressure power steering system on automobile daily popularization, the people to operates when the portability and the road feeling request also day by day enhance, however t

17、he hydraulic pressure power steering system has many shortcomings actually: Because its itself structure had decided it is unable to guarantee vehicles rotates the steering wheel when any operating mode, all has the ideal operation stability, namely is unable simultaneously to guarantee time the low

18、 speed changes the portability and the high speed time operation stability;The automobile changes the characteristic to drive the pilot technical the influence to be serious; The steering ratio is fixed, causes the motor turning response characteristic along with changes and so on vehicle speed, tra

19、nsverse acceleration to change, the pilot must aim at the motor turning characteristic peak-to-peak value and the phase change ahead of time carries on certain operation compensation, thus controls the automobile according to its wish travel. Like this increased pilot's operation burden, also ca

20、uses in the motor turning travel not to have the security hidden danger; But hereafter appeared the electrically controlled hydraulic booster system, it increases the velocity generator in the traditional hydraulic pressure power steering system foundation, enables the automobile along with the vehi

21、cle speed change automatic control force size, has to a certain extent relaxed the traditional hydraulic pressure steering system existence question.At present our country produces on the commercial vehicle and the passenger vehicle uses mostly is the electrically controlled hydraulic pressure boost

22、 steering system, it is quite mature and the application widespread steering system. Although the electrically controlled hydraulic servo alleviated the traditional hydraulic pressure from certain degree to change between the portability and the road feeling contradiction, however it did not have fu

23、ndamentally to solve the HPS system existence insufficiency, along with automobile microelectronic technology development, automobile fuel oil energy conservation request as well as global initiative environmental protection, it in aspect and so on arrangement, installment,leak-proof quality, contro

24、l sensitivity, energy consumption, attrition and noise insufficiencies already more and more obvious, the steering system turned towards the electrically operated boost steering system development.The electrically operated boost steering system is the present motor turning system development directi

25、on, its principle of work is: EPS system ECU after comes from the steering wheel torque sensor and the vehicle speed sensor signal carries on analysis processing, controls the electrical machinery to have the suitable boost torque, assists the pilot to complete changes the operation. In the last few

26、 years, along with the electronic technology development, reduces EPS the cost to become large scale possibly, Japan sends the car company, Mitsubishi Car company, this field car company, US's Delphi automobile system company, TRW Corporation and Germany's ZF Corporation greatly all one afte

27、r another developsEPS.Mercedes2Benz 和Siemens Automotive Two big companies invested65,000,000 pounds to use in developing EPS, the goal are together load a car to 2002, yearly produce 300 ten thousand sets, became the global EPS manufacturer. So far, the EPS system in the slight passenger vehicle, on

28、 the theater box type vehicle obtains the widespread application, and every year by 300 ten thousand speed development.Steering is the term applied to the collection of components, linkages, etc. which allow for a vessel (ship, boat or vehicle (car to follow the desired course. An exception is the c

29、ase of rail transport by which rail tracks combined together with railroad switches provide the steering function.The most conventional steering arrangement is to turn the front wheels using a handoperated steering wheel which is positioned in front of the driver, via the steering column, which may

30、contain universal joints to allow it to deviate somewhat from a straight line. Other arrangements are sometimes found on different types of vehicles, for example, a tiller or rearwheel steering. Tracked vehicles such as tanks usually employ differential steering that is, the tracks are made to move

31、at different speeds or even in opposite directions to bring about a change of course.Many modern cars use rack and pinion steering mechanisms, where the steering wheel turns the pinion gear; the pinion moves the rack, which is a sort of linear gear which meshes with the pinion, from side to side. Th

32、is motion applies steering torque to the kingpins of the steered wheels via tie rods and a short lever arm called the steering arm.Older designs often use the recirculating ball mechanism, which is still found on trucks and utility vehicles. This is a variation on the older worm and sector design; t

33、he steering column turns a large screw (the "worm gear" which meshes with a sector of a gear, causing it to rotate about its axis as the worm gear is turned; an arm attached to the axis of the sector moves the pitman arm, which is connected to the steering linkage and thus steers the wheel

34、s. The recirculating ball version of this apparatus reduces the considerable friction by placing large ball bearings between the teeth of the worm and those of the screw; at either end of the apparatus the balls exit from between the two pieces into a channel internal to the box which connects them

35、with the other end of the apparatus, thus they are "recirculated".The rack and pinion design has the advantages of a large degree of feedback and direct steering "feel" it also does not normally have any backlash, or slack. A disadvantage is that it is not adjustable, so that whe

36、n it does wear and develop lash, the only cure is replacement.The recirculating ball mechanism has the advantage of a much greater mechanical advantage, so that it was found on larger, heavier vehicles while the rack and pinion was originally limited to smaller and lighter ones; due to the almost un

37、iversal adoption of power steering, however, this is no longer an important advantage, leading to the increasing use of rack and pinion on newer cars. The recirculating ball design also has a perceptible lash, or "dead spot" on center, where a minute turn of the steering wheel in either di

38、rection does not move the steering apparatus; this is easily adjustable via a screw on the end of the steering box to account for wear, but it cannot be entirely eliminated or the mechanism begins to wear very rapidly. This design is still in use in trucks and other large vehicles, where rapidity of

39、 steering and direct feel are less important than robustness, maintainability,and mechanical advantage. The much smaller degree of feedback with this design can also sometimes be an advantage; drivers of vehicles with rack and pinion steering can have their thumbs broken when a front wheel hits a bu

40、mp, causing the steering wheel to kick to one side suddenly (leading to driving instructors telling students to keep their thumbs on the front of the steering wheel, rather than wrapping around the inside of the rim. This effect is even stronger with a heavy vehicle like a truck; recirculating ball

41、steering prevents this degree of feedback, just as it prevents desirable feedback under normal circumstances.The steering linkage connecting the steering box and the wheels usually conforms to a variation of Ackermann steering geometry, to account for the fact that in a turn, the inner wheel is actu

42、ally traveling a path of smaller radius than the outer wheel, so that the degree of toe suitable for driving in a straight path is not suitable for turns.As vehicles have become heavier and switched to front wheel drive, the effort to turn the steering wheel manually has increased - often to the poi

43、nt where major physical exertion is required. To alleviate this, auto makers have developed power steering systems. There are two types of power steering systemshydraulic and electric/electronic. There is also a hydraulic-electric hybrid system possible.A hydraulic power steering (HPS uses hydraulic

44、 pressure supplied by an engine-driven pump to assist the motion of turning the steering wheel. Electric power steering (EPS is more efficient than the hydraulic power steering, since the electric power steering motor only needs to provide assist when the steering wheel is turned, whereas the hydrau

45、lic pump must run constantly. In EPS the assist level is easily tunable to the vehicle type, road speed, and even driver preference. An added benefit is the elimination of environmental hazard posed by leakage and disposal of hydraulic power steering fluid.An outgrowth of power steering is speed adj

46、ustable steering, where the steering is heavily assisted at low speed and lightly assisted at high speed. The auto makers perceive that motorists might need to make large steering inputs while manoeuvering for parking, but not while traveling at high speed. The first vehiclewith this feature was the

47、 Citroën SM with its Diravi layout, although rather than altering the amount of assistance as in modern power steering systems, it altered the pressure on a centring cam which made the steering wheel try to "spring" back to the straight-ahead position. Modern speed-adjustable power st

48、eering systems reduce the pressure fed to the ram as the speed increases, giving a more direct feel. This feature is gradually becoming commonplace across all new vehicles.Four-wheel steering (or all wheel steering is a system employed by some vehicles to increase vehicle stability while maneuvering

49、 at high speed, or to decrease turning radius at low speed.In most four-wheel steering systems, the rear wheels are steered by a computer and actuators. The rear wheels generally cannot turn as far as the Alternatively, several systems, including Delphi's Quadrasteer and the system in Honda'

50、s Prelude line, allow for the rear wheels to be steered in the opposite direction as the front wheels during low speeds. This allows the vehicle to turn in a significantly smaller radius sometimes critical for large trucks or vehicles with trailers.汽車轉向系統隨著汽車電子技術的迅猛發展,人們對汽車轉向操縱性能的要求也日益提高。汽車轉向系統已從傳統機

51、械轉向、液壓助力轉向(Hydraulic Power Steering,簡稱HPS 、電控液壓助力轉向( Elect ric Hydraulic PowerSteering ,簡稱EHPS , 發展到電動助力轉向系統(Elect ric Power Steering ,簡稱EPS ,最終還將過渡到線控轉向系統(Steer By Wire ,簡稱SBW。機械轉向系統是指以駕駛員的體力作為轉向能源,其中所有傳力件都是機械的,汽車的轉向運動是由駕駛員操縱方向盤,通過轉向器和一系列的桿件傳遞到轉向車輪而實現的。機械轉向系由轉向操縱機構、轉向器和轉向傳動機械3大部分組成。通常根據機械式轉向器形式可以分為

52、:齒輪齒條式、循環球式、蝸桿滾輪式、蝸桿指銷式。應用最廣的兩種是齒輪齒條式和循環球式(用于需要較大的轉向力時 。在循環球式轉向器中,輸入轉向圈與輸出的轉向搖臂擺角是成正比的;在齒輪齒條式轉向器中,輸入轉向圈數與輸出的齒條位移是成正比的。循環球式轉向器由于是滾動摩擦形式,因而正傳動效率很高,操作方便且使用壽命長,而且承載能力強,故廣泛應用于載貨汽車上。齒輪齒條式轉向器與循環球式相比,最大特點是剛性大,結構緊湊重量輕,且成本低。由于這種方式容易由車輪將反作用力傳至轉向盤,所以具有對路面狀態反應靈敏的優點,但同時也容易產生打手和擺振等現象,且其承載效率相對較弱,故主要應用于小汽車及輕型貨車上,目前大

53、部分低端轎車采用的就是齒輪齒條式機械轉向系統。隨著車輛載重的增加以及人們對車輛操縱性能要求的提高,簡單的機械式轉向系統已經無法滿足需要,動力轉向系統應運而生,它能在駕駛員轉動方向盤的同時提供助力,動力轉向系統分為液壓轉向系統和電動轉向系統2 種。其中液壓轉向系統是目前使用最為廣泛的轉向系統。液壓轉向系統在機械系統的基礎上增加了液壓系統,包括液壓泵、V 形帶輪、油管、供油裝置、助力裝置和控制閥。它借助于汽車發動機的動力驅動液壓泵、空氣壓縮機和發電機等,以液力、氣力或電力增大駕駛員操縱前輪轉向的力量,使駕駛員可以輕便靈活地操縱汽車轉向,減輕了勞動強度,提高了行駛安全性。液壓助力轉向系統從發明到現在

54、已經有了大約半個世紀的歷史,可以說是一種較為完善的系統,由于其工作可靠、技術成熟至今仍被廣泛應用。它由液壓泵作為動力源,經油管道控制閥向動力液壓缸供油,通過活塞桿帶動轉向機構動作,可通過改變缸徑及油壓的大小來改變助力的大小,由此達到轉向助力的作用。傳統液壓式動力轉向系統一般按液流的形式可以分為:常流式和常壓式2 種類型,也可根據控制閥形式分為轉閥式和滑閥式。隨著液壓動力轉向系統在汽車上的日益普及,人們對操作時的輕便性和路感的要求也日益提高,然而液壓動力轉向系統卻存在許多的缺點: 由于其本身的結構決定了其無法保證車輛在任何工況下轉動轉向盤時,都有較理想的操縱穩定性,即無法同時保證低速時的轉向輕便

55、性和高速時的操縱穩定性; 汽車的轉向特性受駕駛員駕駛技術的影響嚴重; 轉向傳動比固定,使汽車轉向響應特性隨車速、側向加速度等變化而變化,駕駛員必須提前針對汽車轉向特性幅值和相位的變化進行一定的操作補償,從而控制汽車按其意愿行駛。這樣增加了駕駛員的操縱負擔,也使汽車轉向行駛中存在不安全隱患;而此后出現了電控液壓助力系統,它在傳統的液壓動力轉向系統的基礎上增加速度傳感器,使汽車能夠隨著車速的變化自動調節操縱力的大小,在一定程度上緩和了傳統的液壓轉向系統存在的問題。目前我國生產的商用車和轎車上采用的大多是電控液壓助力轉向系統,它是比較成熟和應用廣泛的轉向系統。盡管電控液壓助力裝置從一定程度上緩解了傳統的液壓轉向中輕便性和路感之間的矛盾,然而它還是沒有從根本上解決HPS 系統存在的不足,隨著汽車微電子技術的發展,汽車燃油節能的要求以及全球性倡導環保,其在布置、安裝、密封性、操縱靈敏度、能量消耗、磨損與噪聲等方面的不足已越來越明顯,轉向系統向著電動助力轉向系統發展。電動助力轉向系統是現在汽車轉向系統的發展方向,其工作原理是:EPS 系統的ECU 對來自轉向盤轉矩傳感器和車速傳感器的信號進行分析處理后,控制電機產生適