車輛設(shè)計(jì)外文翻譯

1、<p><b>　　翻譯原文</b></p><p>　　624 Race Car Vehicle Dynamics</p><p>　　Besides providing linear motion the restraint device must provide lateral force reactions between the sprung an

2、d unsprung masses. In so doing it is most desirable that the forces are transmitted only in a purely lateral sense, with no vertical component. For example, if a Panhard bar (track bar) is utilized, the slope of the bar

3、in the rear view dictates the</p><p>　　force coupling. If it is horizontal the coupling is zero. If it is sloped the coupling will either lift the sprung mass or pull it down depending on the direction of co

4、rnering and the slope of the bar. Some considerations in the design of a track bar include whether it is normally in tension or compression. For circle track racing, always turning left means</p><p>　　that t

5、he bar should be attached to the body on the right side and to the axle on the left assuring that it is always in tension when cornering.</p><p>　　The pair of arms, the A-arm, and the sliding pin tend to hav

6、e very low vertical-lateral coupling. The Panhard bar and the Watts linkage will always have some, but with attention to detail it can be minimized. This coupling effect must be controlled as much as possìble becaus

7、e it tends to vary with the ride height and roll angle positions of the suspensìon.</p><p>　　By keeping the angle small, the changes will be small and the effect minimized.</p><p>　　17.5 Fr

8、ont Suspensions</p><p>　　lntroduction</p><p>　　Many types of front suspensions have been used over the years. They include various beam type axles with steering via kingpins at each end of the a

9、xle, the parallel trailing arm type such as the VW, the Morgan sliding pillar type, and the Chevrolet Dubonnet. In recent history, passenger car designs have come down to basically two types: the</p><p>　　Ma

10、cPherson Strut and the SLA (Short-Long-Arm).</p><p>　　This chapter will deal only with the last two mentioned as these make up the majority of front suspensions that will be encountered. The other types suff

11、er from either high bending loads, poor geometry, high friction， or a combination of these problems. The best way to discuss each type is to go through the design process step by step. For each step a</p><p>

12、;　　decision has to be made that is often a compromise. By discussing these decisions, hopefully a feeling for the limitations of the design will develop.</p><p>　　Front Suspension Design lssues-General</p

13、><p>　　The frist task in designing a front suspension of any type is to establish the packaging parameters that are fixed， or absolutely cannot be changed for whatever reason (see Figure 17.17). These should be

14、 listed so that they are not overlooked. The next task is to package</p><p>　　the wheel, tire, brakes, and bearings. This is done in car position, so the track width has to be known. If it is not yet establi

15、shed, it should be made as wide as practical. This sounds evasive, but there are trade-offs in everything, even things as simple as choosing the track width. For example, what do the rules allow? What is the predominant

16、race</p><p>　　track type on which the car will run? Is top speed, thus low frontal area important? Are slow-speed tight street circuits of concern? All these issues can affect the decision on the basic track

17、 width!</p><p>　　Tire size and rim diameter and width must be settled. The specific wheel manufacturer needs to be known and a cross section of the wheel is desirable for optimizing the use of that wheel. Ti

18、re sizes are usually limited by the sanctioning body rules. In general, use all the tire they will Iet you get away with. Another point is to always design for the latest</p><p>　　sizes being developed by th

19、e suppliers; this guarantees that the latest compounds and constructions will fit your car. Remember, the tire is the single most important chassis component on the car.</p><p>　　The wheel offset is worked o

20、ut in conjunction with fitting the brake caliper to clear the inside surface of the wheel. Once the caliper is located, this automatically locates the brake rotor. With the rotor location comes the absolute farthest outb

21、oard location for the lower ball joint. Wheel bearings need to be looked at soon, as ideally they should be located such that the tire center is between the two rows of balls or rollers (to minimize loads on the bearing

22、s).</p><p>　　Now that the lower ball joint cross car boundary (lateral position) has been set, the height of the lower ball joint comes next. In production cars it must be above a 5-in. wash rack clearance r

23、equirement, but on race cars it should be made as low as possible for structural reasons. Usually there is no rule but some practical considerations such as deflated tire ground clearance might be in order. If it is tota

24、lly inside the wheel all it has to do is clear the wheel and the brake rotor under all</p><p>　　The decision about the kingpin angle in the front view is the next order ofbusiness. The issues here become scr

25、ub radius, spindle length, and kingpin angle. They are interrelated and a compromise is needed. If you want a certain scrub radius you now have two points established, i.e., the lower ball joint and the ground contact po

26、int of the kingpin (set by the scrub radius)-一the kingpin angle becomes fixed automatically. If you want a certain kingpin angle then the scrub radius will not necessari</p><p>　　Kingpin ang1e affects the pe

27、rformance of the car when the wheels are steered. One concept that should be understood is that the more the kingpin angle the more the car is lifted when it is steered. This is one source of steering returnability, the

28、weight of the car returns the steering to center. The amount the car is lifted is also a function of the spindle length where a longer spindle means more lift.</p><p>　　The camber of the wheels when steered

29、is a function of the kingpin angle and the caster angle. With no kingpin angle (and no caster angle) there is no camber change with steer lock. As kingpin is added (but still no caster) the wheel will "lose" ca

30、mber with steer lock, or in other words it will change in a direction giving positive camber on the outside</p><p>　　wheel.60 As caster is added this modifies the effect of kingpin. With positive caster and

31、no kingpin angle, the whee1 gains negative camber on the outside wheel and positive camber on the inside wheel. Thus caster can add favorable camber angle to the effects of kingpin angle. In other words, the reason that

32、low kingpin angles are desirable is that kingpin angle subtracts from the negative camber gain due to caster on the outside wheel.</p><p>　　The decision on a rack location depends on several packaging factor

33、s such as engine location and orientation，front-wheel drive vs. rear-wheel drive, whether it is to be high- or low-mounted, etc. In addition there are performance reasons for choosing the rack location.</p><p&

34、gt;　　First we must assume that every structure is a spring and should be treated as such. As an example the rack mounting stiffness versus the upper or lower control arm mounting stiffness to the chassis will not necessa

35、rily be the same. Therefore, when a cornering force is applied, any difference in the lateral displacement of the ball joints in relation to</p><p>　　the tie rod outer pivot will cause a steer angle. To assu

36、re stability it is better to have lateral force deflection toe-out (lateral force understeer) rather than toe-in. We can assure that this happens by the proper location of the rack. If a high-mounted rack is required it

37、must be behind wheel center and if it is low-mounted then it must be ahead of wheel center as shown by the shaded areas in Figure 17.17.</p><p>　　Structural requirements for the suspension design must always

38、 be considered when packaging each element of the total system. Control arms that have one leg straight across from the ball joint are superior in system stiffness to arms that are splayed. Establishing linkage ratios fo

39、r the spring, shock, and stabilizer bar as close to 1: 1 as possible will provide more direct load paths thus improving system stiffness while providing a lighter overall design.</p><p>　　This is the most co

40、mmon form of front suspension and can be used as a rear suspension very sily.The toe link is grounded to the chassis(instead of attaching to a rack) as shown in Figure17.30(b).If a front suspension were to be used as the

41、 rear suspension this style is easy to adapt with one one important consideration.The left front components should be installed as the right rear corner and the right front as the left rear.The reason these are “turned a

42、round”is that geometric toe consideration</p><p>　　A minor variation of this design is the case where the toe link does not attach to the chassis;rather it is attached to either the upper or the lower contro

43、l arm (shown to the lower arm in Figure 17.18(c)).This can be contemplated only when the toe link outer pivot is very close to the same height as the ball joint.This is called”an ungrounded”toe link.The ride toe characte

44、ristics are not always obvious on this type,especially when there is significant caster change present.For best results a co</p><p>　　Upper A-arm with Three Links</p><p>　　Sometimes a lower A-ar

45、m is not practical for packaging reasons.An equivalent suspension geometry using three individual straight links in place of a lower A-arm and a toe link along with an upper A-arm can provide very good geometry.The links

46、 can be arranged basically in two nontrailing basically lateral/diagonal links and another lateral link acting as a toe link.The trailing link arrangement will have more of a problem getting the toe curve to be linear,an

47、d will have other parameters controlle</p><p>　　Lower A-arm and Three links</p><p>　　A system basically opposite of that described above is also a viable suspension in the SLA family.In this cas

48、e the upper arm is formed by two of the links.Again a virtual center may be created to achieve a particular feature that is unobtainable with a ball jointed A-arm.The use of one link trailing and the other straight later

49、al is also possible but not generally recommended.</p><p>　　H-arm and A-arm</p><p>　　An H-arm functions as three links in this example and is similar to the A-arm with an ungrounded toe link(see

50、Figure 17.30(c)).It can be used either as an upper arm or a lower arm in a rear suspension.When it is used,the inner pivot axis of the H-arm must be parallel to the inner pivot axis of the A-arm or else binding will occu

51、r with suspension travel due to the attempt to rotate the knuckle(caster change) thus twisting the H –arm.This means the side view swing arm instant center must be at infi</p><p>　　H-arm lower and camber lin

52、k</p><p>　　The use of an H-type lower arm and a single lateral upper link is a special case where the H-arm is being asked to perform the function of four links instead of just three.It accomplishes this by

53、reacting all braking loads as a torsional input .Reactions to all wheel center inputs in the longitudinal direction end up putting the H-arm in torsion over its length.The structural requirements of the arm become quite

54、different in this case.The single upper link acts only in the front view and contrib</p><p><b>　　Five-link</b></p><p>　　A system utilizing five individual links can make a very satis

55、factory suspension.The placement and orientation is similar to the three-link and A-arm mentioned above with the A-arm now formed by two links;two variations are shown in Figure 17.33 and 17.34.The kinematics are very fl

56、exible with this type of design where the issue to get the front view kinematics desired without compromising the side view geometry.Another major reason for doing a five-link is to obtain a short spindle length and a &l

57、t;/p><p>　　A caution in using this design is that the lateral diagonal pairing of upper and lower links to simulate A-arms is preferred to pure lateral and pure trailing links to form the arms.This is because t

58、he rate of change of the side view geometry is generally too high with the trailing arm concept.Also a trailing arm must be packaged inboard of the wheel edge which results in a spindle length at least as large as half t

59、he tire section width.See Figure 17.34 for an explanation of this concept.Example</p><p>　　17.7Beam Axle Rear Suspensions</p><p>　　As mentioned earlier in the general section on beam-type axles

60、there are five basic kinematic properties that need to be controlled by the suspension links.The wheel path,anti-lift,and anti-squat are controlled by the side view instant center.The roll center height and roll steer ar

61、e controlled by the roll axis.All loads that occur between the sprung and unsprung masses are reacted by the suspension links.The fore and aft loads such as braking and acceleration are coupled through the side view i<

62、;/p><p>　　Four bar links </p><p>　　The very first section of this chapter discussed degrees of freedom and motion path and it was shown that a beam axle suspension has two motion paths,therefore,th

63、e motion can be controlled by four links.There are various ways to arrange those four links to achieve a workable suspensions.The list below includes some of the most popular.</p><p>　　Basic four bar link<

64、;/p><p>　　Figure 17.35 is representative of this style of geometry.The side view instant center is determined by projecting or extending a line through the ends of both the upper and lower arms until they inter

65、sect.Normally the intersection will occur 100 in.or so ahead of the wheel center and will have a height somewhere between ground level and the wheel center.This part of the analysis is simple and straightforward and can

66、be done in one view of the design.</p><p>　　The roll axis determination is a little more complicated because it involves looking at things in both the side view and the plan (or top) view.The roll axis is a

67、line connecting the two lateral restraint points.These lateral restraint points were discussed in the general section on beam axles.For the basic four bar link the pair of upper control arms are angled in the plan view a

68、nd therefore have an intersecting point which is a lateral restraint point ,marked as “A”in the figure.The same is do</p><p>　　You will note that in the plan view the upper and lower arm intersection points

69、lie on the centerline of the car.This is because the right and left sides of the suspension are exactly the same.If they were not the same you would still use the same procedures to understand the geometry,but you might

70、end up with a roll axis off center or one that angles in the plan view.This may or may not be desirable depending on the kind of performance that is needed.</p><p>　　When designing a four bar link rear suspe

71、nsion the side view geometry is adjusted by raising or lowering the pivots of the links relative to each other to get them to aim toward the desired instant center.The absolute and relative lengths of the upper and lower

72、 arms in the side view affect the rate of change of the side view instant center as well as how the axle housing rotates with wheel travel.This rotation is important to maintaining control over the propshaft joint angles

73、.The change in pini</p><p>　　Front Suspension Design Issues-SLA</p><p>　　The Short-Long Arm (SLA) suspension is the choice of designers without question for its ability to meet desired performan

74、ce objectives with minimum compromise.</p><p>　　The design starts with the basic package as described above. The details of the track width, the wheel size, the tire, the brakes, etc., bring about the locati

75、on available for the lower ball joint. The upper ball joint is located either via kingpin angle requirements or by scrub radius requirements. There is a little more freedom with the SLA that is not available to the strut

76、 design and that is the choice of a short knuckle or a tall knuckle.</p><p>　　The short knuckle means the upper ball joint is located basically within the diameter of the wheel. With high offset and large-di

77、ameter wheels the kingpin angle can be kept small (while achieving small spindle lengths and scrub radius) by tucking the upper ball joint into the wheel.</p><p>　　To reduce the loads on the control arms and

78、 other suspension components, it is desirable to have a long kingpin length, that is, separate the upper and lower ball joints as much as possible. Depending on detai!s of the installation, the short knuckle may yield le

79、ss than optimum kingpin length. The other alternative is the tall knuckle where the upper ball</p><p>　　joint is above the tire. In the tall knuckle design the ball joints naturally have a very large span an

80、d thus reduce reaction loads. This option also allows reasonable kingpin angles while achieving desired spindle length and scrub radius. Another advantage for the tall knuckle is that build errors will result in smaller

81、geometry errors than with short knuckle designs. Some negatives to the tall knuckle, of course, are the added structural requirements of the knuckle, and the limitation of never</p><p>　　With the upper and l

82、ower ball joint locations established, the tie rod outer point should also be set per the requirements established in Chapter 19 on steering geometry.</p><p>　　Front View Geometry</p><p>　　The f

83、ront view geometry can now start. The front view swing arm instant center is uniquely deternmined by the desired roll center height and roll camber (see Figure 17.18). The desired roll camber sets the front view swing ar

84、m length (location of line A-A) as follows:</p><p>　　The front view instant center height is set by projecting a line from the tire center ground contact patch through the desired roll center height. The ins

85、tant center must lie on this line. Now we can project lines from both ball joints to the instant center. These become the centerlines of the upper and lower control arm planes as projected into the vertical plane through

86、 the wheel center. Packaging requirements will establish the length of the lower control arm but it should be rnade as long as</p><p>　　To finish the front view geometry， the tie rod and rack location should

87、 be roughedin. This is done by projecting a line through the tie rod outer point (established in Chapter 19 on steering) and the front view instant center. The correct tie rod length is then established for a linear ride

88、 toe curve. This length will be modified after the side view geometry is completed, but doing it now is a good idea to help plan a realistic rack location.</p><p>　　624 賽車動(dòng)力特性</p><p>　　除了提供直線運(yùn)動(dòng)外

89、，安全裝置還要在安裝彈簧和非安裝彈簧的部件之間提供側(cè)向反力。這樣做是最可取的，力只在側(cè)面有分力，在垂直方向上沒有分力。例如，如果利用一個(gè)潘哈德桿（跟蹤條），后視圖中桿的傾斜度要求有力耦合。如果是橫向的耦合是零。如果是傾斜的耦合要么解除簧載質(zhì)量或壓下來取決于轉(zhuǎn)彎的方向和桿的傾斜度。在一個(gè)跟蹤條的設(shè)計(jì)中考慮的因素包括是否通常在拉伸或壓縮狀態(tài)。對于循環(huán)的軌道賽車，總是向左轉(zhuǎn)的條件意味著該桿應(yīng)該連在車身的右側(cè)和軸的左側(cè)，確保轉(zhuǎn)彎時(shí)桿始終在緊張狀

90、態(tài)。</p><p>　?。列偷囊粚M臂和滑銷有非常小的垂直和側(cè)向力偶。潘哈德桿和瓦特連桿總是有一些力偶，但是注意細(xì)節(jié)可以把力偶最小化。這種耦合作用，必須盡可能地控制，因?yàn)樗鶗?huì)隨著車身高度和懸架側(cè)傾角位置變化而變化。通過保持較小的角度，這些變化將很小，而其影響減至最低。</p><p><b>　　17.5前懸架　</b></p><p>

91、<b>　　介紹　</b></p><p>　　許多類型的前懸架已經(jīng)使用了數(shù)年之久。他們包括各種梁式軸通過方向盤憑借關(guān)鍵每個(gè)后面的軸，兩端各軸平行拖臂式如大眾,摩根滑動(dòng)柱式、雪佛蘭開。在最近的歷史、客車設(shè)計(jì)基本上涉及到兩種類型</p><p>　　麥弗遜式前獨(dú)立支撐和航天器(長短臂)。</p><p>　　本章將只處理最后提到的兩個(gè),因?yàn)檫@些構(gòu)

92、成了大部分的遇到的前懸架。其他類型遭受高彎曲載荷,質(zhì)量差幾何學(xué)、高摩擦力,或者一些混合的問題。最好的辦法是去討論每一個(gè)類型的設(shè)計(jì)通過循序漸進(jìn)的過程。每一步的</p><p>　　決定通常是一種妥協(xié)。這些決定,希望探討一種感覺就是設(shè)計(jì)的限制將會(huì)發(fā)展。</p><p>　　前懸架設(shè)計(jì)的普遍的問題</p><p>　　在設(shè)計(jì)的任務(wù)是任何類型的前懸架建立包裝的參數(shù)是固定的,

93、或絕對不能改變在不知什么原因的情況下(見圖17.17)。這些應(yīng)該被列出來,以便他們都沒有被忽略。下一個(gè)任務(wù)是包裝</p><p>　　車輪、輪胎、制動(dòng)器、軸承。在汽車位置這樣做，所以偏斜的寬度必須認(rèn)識(shí)。如果它沒有建立,應(yīng)該被制造跟實(shí)際的一樣。這聽起來有點(diǎn)兒閃爍其詞,但也有權(quán)衡每一件事,即使事情像選擇軌跡寬度一樣簡單。例如,這個(gè)規(guī)則允許嗎?什么是主要的關(guān)于汽車將要跑的比賽類型?最高的速度,因此低的前面的區(qū)域重要嗎?

94、低速的緊街電路是關(guān)心嗎?所有的這些問題會(huì)影響決策的基本軌跡寬度!</p><p>　　輪胎的尺寸，環(huán)直徑和寬度必須被解決。具體的車輪制造商需要被認(rèn)識(shí)并且輪子上的十字形部件是可取的，作為輪子的最優(yōu)使用。輪胎的尺寸通常被制定的車身規(guī)則所限制。一般來說,用所有的輪胎會(huì)讓你僥幸取走。另一點(diǎn)是供應(yīng)商總是設(shè)計(jì)正在發(fā)展的最新的設(shè)計(jì)尺寸</p><p>　　,這保證了最新的化合物和結(jié)構(gòu)將更適合你的車。記住

95、,在這個(gè)車上，輪胎是最最重要的底盤部件。</p><p>　　車輪補(bǔ)償被解決，一起來適應(yīng)剎車測徑器去清洗輪胎的內(nèi)表面，一旦測徑器被定位，這個(gè)會(huì)自動(dòng)定位剎車轉(zhuǎn)子。與轉(zhuǎn)子位置是絕對最遠(yuǎn)的外側(cè)定位是低球接頭。不久，轉(zhuǎn)盤軸承必須被看著,作為理想,他們應(yīng)該位于兩個(gè)成排的球或滾筒(最小化的軸承)的輪胎之間的中心?！　?lt;/p><p>　　現(xiàn)在,較低的球車邊(橫向位置的十字架)已經(jīng)確定,高度較低的球接下

96、來被引進(jìn)，在生產(chǎn)汽車必須位于5英寸以上.滿足清洗要求,但在賽車中它應(yīng)該被制造和車架上的要求一樣低。通常沒有規(guī)則,但一些實(shí)際的考慮,如氣胎地上間隙。如果將它完全放在車輪中，它所有的作用就是清洗輪胎和在路況行駛下的制動(dòng)輪?！　?lt;/p><p>　　這個(gè)關(guān)于止推角的決定在前視角下是商業(yè)的下一步?jīng)Q定。這個(gè)問題在這里成為刷洗半徑、紡錘狀的長度和支撐角。他們都是互相聯(lián)系的，并且妥協(xié)是必要的。如果你想要一個(gè)特定刷洗半徑,現(xiàn)在你

97、有兩點(diǎn)需要確定,即建立低球接頭和地面接觸點(diǎn)的支撐(由刷洗半徑)-這個(gè)止推角被自動(dòng)的固定，如果你想要一個(gè)特定支撐角，然后刷洗半徑不一定是你想要的東西?；旧?在一個(gè)后輪驅(qū)動(dòng)車上盡可能快的把低球接頭推出并且以較小的角度運(yùn)行，小于8度，并接受了半徑的結(jié)果。如果你正在處理前輪驅(qū)動(dòng)車,你必須減少車輛軸長度和消極刷洗半徑。這可能導(dǎo)致主銷角度高達(dá)16度,但你將不得不接受它或找到另一個(gè)聰明的辦法。</p><p>　　主銷傾角影

98、響汽車的表現(xiàn)當(dāng)車輪被操縱時(shí)。這一概念的理解是,當(dāng)車輪被操縱時(shí)主傾角越大，汽車被提升的角度越大。這是一個(gè)返回操縱的來源，汽車的重量轉(zhuǎn)向到中心;如果執(zhí)行失敗,將返回。車的數(shù)量被提升 。</p><p>　　在曲面的車輪駕駛時(shí)是主傾角和外傾角的作用。沒有主銷傾角角度(不)是沒有曲面變化與引導(dǎo)鎖。作為支撐加(但仍然沒有腳輪)車輪將失去“曲面同鎖定甚至換句話說,它將改變方向,給予積極的曲面在外輪上，正如腳輪被補(bǔ)充關(guān)鍵的作用