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譯文題目： The Automobile Steering System
汽車轉(zhuǎn)向系統(tǒng)
學(xué)生姓名：
?！ I(yè)：
所在學(xué)院：
指導(dǎo)教師：
職 稱：
2013年02月19日
The Automobile Steering System
Along?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?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?system?(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?diverter?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?world?-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?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?ease?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?low.?Because?this?way?passes?on?easily?by?the?wheel?the?reacting?force?to?the?steering?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?applies?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?type?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?steering?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?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,?enables?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?its?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?cylinder?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?atmospheric?pressure?type?2?kind?of?types,?also?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?the?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?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,?transverse?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?causes?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?vehicle?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?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?fundamentally?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,?control?sensitivity,?energy?consumption,attrition?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?direction,?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?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.after.another.develops.EPS.Mercedes2Benz.and.Siemens?Automotive?Two?big?companies?invested?65,000,000?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?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?case?of?rail?transport?by?which?rail?tracks?combined?together?with?railroad?switches?provide?the?steering?function.?
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..This.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;?the?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?wheels.?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?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?when?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?universal?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?direction?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?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?bump,?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?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?actually?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?point?where?major?physical?exertion?is?required.?To?alleviate?this,?auto?makers?have?developed?power?steering?systems.?There?are?two?types?of?powersteering.system.hydraulic?and?electric/electronic.?There?is?also?a?hydraulic-electric?hybrid?system?possible.?
A?hydraulic?power?steering?(HPS)?uses?hydraulic?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?hydraulic?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?adjustable?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?vehicle?with?this?feature?was?the?Citro?n?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?steering?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?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'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.
隨著汽車電子技術(shù)的迅猛發(fā)展,人們對(duì)汽車轉(zhuǎn)向操縱性能的要求也日益提高。汽車轉(zhuǎn)向系統(tǒng)已從傳統(tǒng)機(jī)械轉(zhuǎn)向、液壓助力轉(zhuǎn)向(Hydraulic?Power?Steering?,簡(jiǎn)稱HPS)?、電控液壓助力轉(zhuǎn)向(?Elect?ric?Hydraulic?PowerSteering?,?簡(jiǎn)稱EHPS)?,?發(fā)展到電動(dòng)助力轉(zhuǎn)向系統(tǒng)(Elect?ric?Power?Steering?,簡(jiǎn)稱EPS)?,最終還將過(guò)渡到線控轉(zhuǎn)向系統(tǒng)(Steer?By?Wire?,簡(jiǎn)稱SBW)。?
機(jī)械轉(zhuǎn)向系統(tǒng)是指以駕駛員的體力作為轉(zhuǎn)向能源,其中所有傳力件都是機(jī)械的,汽車的轉(zhuǎn)向運(yùn)動(dòng)是由駕駛員操縱方向盤(pán),通過(guò)轉(zhuǎn)向器和一系列的桿件傳遞到轉(zhuǎn)向車輪而實(shí)現(xiàn)的。機(jī)械轉(zhuǎn)向系由轉(zhuǎn)向操縱機(jī)構(gòu)、轉(zhuǎn)向器和轉(zhuǎn)向傳動(dòng)機(jī)械3大部分組成。?
通常根據(jù)機(jī)械式轉(zhuǎn)向器形式可以分為:齒輪齒條式、循環(huán)球式、蝸桿滾輪式、蝸桿指銷式。應(yīng)用最廣的兩種是齒輪齒條式和循環(huán)球式(用于需要較大的轉(zhuǎn)向力時(shí))?。在循環(huán)球式轉(zhuǎn)向器中,輸入轉(zhuǎn)向圈與輸出的轉(zhuǎn)向搖臂擺角是成正比的;在齒輪齒條式轉(zhuǎn)向器中,輸入轉(zhuǎn)向圈數(shù)與輸出的齒條位移是成正比的。循環(huán)球式轉(zhuǎn)向器由于是滾動(dòng)摩擦形式,因而正傳動(dòng)效率很高,操作方便且使用壽命長(zhǎng),而且承載能力強(qiáng),故廣泛應(yīng)用于載貨汽車上。齒輪齒條式轉(zhuǎn)向器與循環(huán)球式相比,最大特點(diǎn)是剛性大,結(jié)構(gòu)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(zhuǎn)向盤(pán),所以具有對(duì)路面狀態(tài)反應(yīng)靈敏的優(yōu)點(diǎn),但同時(shí)也容易產(chǎn)生打手和擺振等現(xiàn)象,且其承載效率相對(duì)較弱,故主要應(yīng)用于小汽車及輕型貨車上,目前大部分低端轎車采用的就是齒輪齒條式機(jī)械轉(zhuǎn)向系統(tǒng)。?
隨著車輛載重的增加以及人們對(duì)車輛操縱性能要求的提高,簡(jiǎn)單的機(jī)械式轉(zhuǎn)向系統(tǒng)已經(jīng)無(wú)法滿足需要,動(dòng)力轉(zhuǎn)向系統(tǒng)應(yīng)運(yùn)而生,它能在駕駛員轉(zhuǎn)動(dòng)方向盤(pán)的同時(shí)提供助力,動(dòng)力轉(zhuǎn)向系統(tǒng)分為液壓轉(zhuǎn)向系統(tǒng)和電動(dòng)轉(zhuǎn)向系統(tǒng)2?種。其中液壓轉(zhuǎn)向系統(tǒng)是目前使用最為廣泛的轉(zhuǎn)向系統(tǒng)。
?液壓轉(zhuǎn)向系統(tǒng)在機(jī)械系統(tǒng)的基礎(chǔ)上增加了液壓系統(tǒng),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(fā)動(dòng)機(jī)的動(dòng)力驅(qū)動(dòng)液壓泵、空氣壓縮機(jī)和發(fā)電機(jī)等,以液力、氣力或電力增大駕駛員操縱前輪轉(zhuǎn)向的力量,使駕駛員可以輕便靈活地操縱汽車轉(zhuǎn)向,減輕了勞動(dòng)強(qiáng)度,提高了行駛安全性。
?液壓助力轉(zhuǎn)向系統(tǒng)從發(fā)明到現(xiàn)在已經(jīng)有了大約半個(gè)世紀(jì)的歷史,可以說(shuō)是一種較為完善的系統(tǒng),由于其工作可靠、技術(shù)成熟至今仍被廣泛應(yīng)用。它由液壓泵作為動(dòng)力源,經(jīng)油管道控制閥向動(dòng)力液壓缸供油,通過(guò)活塞桿帶動(dòng)轉(zhuǎn)向機(jī)構(gòu)動(dòng)作,可通過(guò)改變缸徑及油壓的大小來(lái)改變助力的大小,由此達(dá)到轉(zhuǎn)向助力的作用。傳統(tǒng)液壓式動(dòng)力轉(zhuǎn)向系統(tǒng)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(jù)控制閥形式分為轉(zhuǎn)閥式和滑閥式。?
隨著液壓動(dòng)力轉(zhuǎn)向系統(tǒng)在汽車上的日益普及,人們對(duì)操作時(shí)的輕便性和路感的要求也日益提高,然而液壓動(dòng)力轉(zhuǎn)向系統(tǒng)卻存在許多的缺點(diǎn):?①由于其本身的結(jié)構(gòu)決定了其無(wú)法保證車輛在任何工況下轉(zhuǎn)動(dòng)轉(zhuǎn)向盤(pán)時(shí),都有較理想的操縱穩(wěn)定性,即無(wú)法同時(shí)保證低速時(shí)的轉(zhuǎn)向輕便性和高速時(shí)的操縱穩(wěn)定性;?②汽車的轉(zhuǎn)向特性受駕駛員駕駛技術(shù)的影響嚴(yán)重;?③轉(zhuǎn)向傳動(dòng)比固定,使汽車轉(zhuǎn)向響應(yīng)特性隨車速、側(cè)向加速度等變化而變化,駕駛員必須提前針對(duì)汽車轉(zhuǎn)向特性幅值和相位的變化進(jìn)行一定的操作補(bǔ)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(fù)擔(dān),也使汽車轉(zhuǎn)向行駛中存在不安全隱患;而此后出現(xiàn)了電控液壓助力系統(tǒng),它在傳統(tǒng)的液壓動(dòng)力轉(zhuǎn)向系統(tǒng)的基礎(chǔ)上增加速度傳感器,使汽車能夠隨著車速的變化自動(dòng)調(diào)節(jié)操縱力的大小,在一定程度上緩和了傳統(tǒng)的液壓轉(zhuǎn)向系統(tǒng)存在的問(wèn)題。
?目前我國(guó)生產(chǎn)的商用車和轎車上采用的大多是電控液壓助力轉(zhuǎn)向系統(tǒng),它是比較成熟和應(yīng)用廣泛的轉(zhuǎn)向系統(tǒng)。盡管電控液壓助力裝置從一定程度上緩解了傳統(tǒng)的液壓轉(zhuǎn)向中輕便性和路感之間的矛盾,然而它還是沒(méi)有從根本上解決HPS?系統(tǒng)存在的不足,隨著汽車微電子技術(shù)的發(fā)展,汽車燃油節(jié)能的要求以及全球性倡導(dǎo)環(huán)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(lái)越明顯,轉(zhuǎn)向系統(tǒng)向著電動(dòng)助力轉(zhuǎn)向系統(tǒng)發(fā)展。
電動(dòng)助力轉(zhuǎn)向系統(tǒng)是現(xiàn)在汽車轉(zhuǎn)向系統(tǒng)的發(fā)展方向,其工作原理是:EPS?系統(tǒng)的ECU?對(duì)來(lái)自轉(zhuǎn)向盤(pán)轉(zhuǎn)矩傳感器和車速傳感器的信號(hào)進(jìn)行分析處理后,控制電機(jī)產(chǎn)生適當(dāng)?shù)闹D(zhuǎn)矩,協(xié)助駕駛員完成轉(zhuǎn)向操作。近幾年來(lái),隨著電子技術(shù)的發(fā)展,大幅度降低EPS的成本已成為可能,日本的大發(fā)汽車公司、三菱汽車公司、本田汽車公司、美國(guó)的Delphi?汽車系統(tǒng)公司、TRW公司及德國(guó)的ZF?公司都相繼研制出EPS。Mercedes2Benz?和Siemens?Automotive?兩大公司共同投資6500萬(wàn)英鎊用于開(kāi)發(fā)EPS?,目標(biāo)是到2002?年裝車,年產(chǎn)300?萬(wàn)套,成為全球EPS?制造商。到目前為止,EPS?系統(tǒng)在輕微型轎車、廂式車上得到廣泛的應(yīng)用,并且每年以300萬(wàn)臺(tái)的速度發(fā)展。
?轉(zhuǎn)向是一個(gè)專業(yè)術(shù)語(yǔ),適用于采集部件,聯(lián)系等,其中允許一艘(艦船)或汽車(轎車)按照預(yù)期的方向行駛.?一個(gè)例外的情況是鐵路運(yùn)輸由路軌組合在一起鐵路道岔提供轉(zhuǎn)向功能。?
許多現(xiàn)代轎車使用齒輪齒條式轉(zhuǎn)向器,在方向盤(pán)末端有轉(zhuǎn)動(dòng)齒輪;該齒輪帶動(dòng)齒條移動(dòng),它是一種線性的齒輪緊密配合,從一邊到一邊。這種運(yùn)動(dòng)把轉(zhuǎn)矩通過(guò)轉(zhuǎn)向橫拉桿和一種叫做轉(zhuǎn)向節(jié)臂的短形臂傳遞給轉(zhuǎn)向輪的主銷。?
以前的設(shè)計(jì)往往采用循環(huán)球式轉(zhuǎn)向器,而這種轉(zhuǎn)向器仍然應(yīng)用在卡車和多用途車輛。這是一種老式的螺母和齒扇設(shè)計(jì)，該轉(zhuǎn)向管柱轉(zhuǎn)動(dòng)大螺絲("蝸輪"),它與一個(gè)齒扇齒輪嚙合,當(dāng)蝸輪轉(zhuǎn)動(dòng)時(shí)，齒扇也隨之轉(zhuǎn)動(dòng)，一個(gè)安裝在齒扇軸上且與轉(zhuǎn)向聯(lián)動(dòng)有關(guān)的搖臂帶動(dòng)轉(zhuǎn)向節(jié)臂?,從而使車輪轉(zhuǎn)動(dòng).?循環(huán)球式轉(zhuǎn)向器通過(guò)安裝滾珠減少螺母和螺桿之間的摩擦;兩根導(dǎo)管和螺母內(nèi)的螺旋管狀通道組合成兩條各自獨(dú)立的封閉的鋼球“流到”。
?齒輪齒條式轉(zhuǎn)向器設(shè)計(jì)具有很大程度的反饋和直接轉(zhuǎn)向"路感";它也通常不會(huì)有任何反彈,或呆滯。缺點(diǎn)是,它是不可調(diào)的,因此當(dāng)它磨損唯一的解決辦法更換。
?循環(huán)球式轉(zhuǎn)向器的優(yōu)點(diǎn)是機(jī)械優(yōu)勢(shì),因此,它被使用在較大較重的車輛,而齒輪齒條式原本僅限于較小和較輕;由于幾乎普遍采用動(dòng)力轉(zhuǎn)向系統(tǒng),不過(guò),這已不再是一個(gè)重要的優(yōu)勢(shì),導(dǎo)致越來(lái)越多地在新型汽車應(yīng)用齒輪齒條式轉(zhuǎn)向器。?循環(huán)球式轉(zhuǎn)向器設(shè)計(jì)在中心也有明顯的沖擊,或"死點(diǎn)"。凡一分鐘交替方向盤(pán)出不來(lái)并不移動(dòng)轉(zhuǎn)向機(jī)構(gòu);這是很容易可調(diào)螺桿的端部來(lái)減少磨損,但它并不能完全消除或機(jī)制開(kāi)始磨損很快。?這項(xiàng)設(shè)計(jì)目前仍在使用中,在卡車和其他大型車輛,也應(yīng)用于迅速轉(zhuǎn)向,路感與穩(wěn)健性,可維護(hù)性,和機(jī)械的優(yōu)勢(shì)相比不太重要的場(chǎng)合。?較小程度的反饋,這樣的設(shè)計(jì)也有時(shí)是一種優(yōu)點(diǎn);當(dāng)前輪碰撞時(shí)，使用齒輪齒條轉(zhuǎn)向的司機(jī)只有自己的大拇指受傷,造成方向盤(pán)揭開(kāi)一邊突然(因?yàn)轳{駛教練告訴學(xué)生把自己的大拇指在前面的方向盤(pán),而非放在左右的內(nèi)邊緣).?這種效果在像卡車一樣的重型汽車更為明顯;循環(huán)球式轉(zhuǎn)向防止這種程度的反饋,只是因?yàn)樗梢栽谡Ｇ闆r下防止可取反饋。?
?轉(zhuǎn)向連鎖連接轉(zhuǎn)向器和車輪通常符合一個(gè)阿克曼轉(zhuǎn)向幾何的變化,它交代了一個(gè)事實(shí):當(dāng)轉(zhuǎn)向是,內(nèi)輪轉(zhuǎn)過(guò)的半徑比外輪小得多，因此適合駕駛的直路,是不適合曲折。
?由于車輛已成為較重而改用前輪驅(qū)動(dòng),為了扭轉(zhuǎn)方向盤(pán)，通常的,主要的是體力。為了解決這一問(wèn)題,汽車業(yè)發(fā)展的動(dòng)力轉(zhuǎn)向系統(tǒng)。?有兩種類型的助力轉(zhuǎn)向系統(tǒng)-液壓和電氣/電子。?還有一種液壓-電動(dòng)混合系統(tǒng)。
?液壓助力轉(zhuǎn)向系統(tǒng)(hps)利用油壓供應(yīng)的一個(gè)發(fā)動(dòng)機(jī)驅(qū)動(dòng)泵,以協(xié)助將方向盤(pán)轉(zhuǎn)轉(zhuǎn)動(dòng)。?電動(dòng)助力轉(zhuǎn)向系統(tǒng)(EPS)方式,是較有效率的液壓助力轉(zhuǎn)向系統(tǒng),由于電動(dòng)助力轉(zhuǎn)向汽車只需要提供協(xié)助時(shí),方向盤(pán)被轉(zhuǎn)動(dòng),而液壓泵必須不斷運(yùn)行。?在EPS的幫助下是很容易調(diào)節(jié)車型,最高車速,甚至駕駛的喜好。?另外一個(gè)好處是,通過(guò)泄漏和處置動(dòng)力轉(zhuǎn)向液消除對(duì)環(huán)境構(gòu)成危險(xiǎn)?。
?動(dòng)力轉(zhuǎn)向的分支是速度可調(diào)轉(zhuǎn)向而轉(zhuǎn)向是大量輔助以低速行駛,稍微協(xié)助高速。?汽車制造商認(rèn)為,當(dāng)要停車時(shí)駕駛?cè)丝赡苄枰龀龃罅哭D(zhuǎn)向投入，但當(dāng)時(shí)高速行駛時(shí)則不然。第一輛有這特點(diǎn)的汽車,是雪鐵龍與其diravi，雖然改變了現(xiàn)代汽車轉(zhuǎn)向系統(tǒng)資金的投入，但它改變了定心凸輪的壓力，使得方向盤(pán)盡力去回到原來(lái)的位置。現(xiàn)代速度可調(diào)式動(dòng)力轉(zhuǎn)向系統(tǒng),當(dāng)速度增長(zhǎng)時(shí)減少了活塞的壓力?,給予更直接的感受。這一特點(diǎn)在所有新車正逐漸成為司空見(jiàn)慣。?
?四輪轉(zhuǎn)向(或全輪轉(zhuǎn)向)是一種系統(tǒng),當(dāng)高速行駛時(shí)能增加車輛穩(wěn)定型，而在低速行駛時(shí)可以減小轉(zhuǎn)彎半徑。
?大多數(shù)的四輪轉(zhuǎn)向系統(tǒng),后輪轉(zhuǎn)向通過(guò)單片機(jī)和驅(qū)動(dòng)器實(shí)現(xiàn)。?后輪一般不能反過(guò)來(lái),有幾個(gè)系統(tǒng),包括Delphi的quadrasteer，該系統(tǒng)在本田的生產(chǎn)前線，當(dāng)前輪低速時(shí)，允許后輪在相反方向轉(zhuǎn)向。這使得車輛轉(zhuǎn)彎半徑較小,有時(shí)應(yīng)用于大型卡車車輛及掛車。