- -34差速器根據(jù)汽車行駛運動學(xué)的要求和實際的車輪、道路以及它們之間的相互關(guān)系表明：汽車在行駛過程中左右車輪在同一時間內(nèi)所滾過的行程往往是有差別的。例如，轉(zhuǎn)彎時外側(cè)車輪的行程總要比內(nèi)側(cè)的長。另外，即使汽車作直線行駛，也會由于左右車輪在同一時間內(nèi)所滾過的路面垂向波形的不同，或由于左右車輪輪胎氣壓、輪胎負(fù)荷、胎面磨損程度的不同以及制造誤差等因素引起左右車輪外徑不同或滾動半徑不相等而要求車輪行程不等。在左右車輪行程不等的情況下，如果采用一根整體的驅(qū)動車輪軸將動力傳給左右車輪，則會由于左右驅(qū)動車輪的轉(zhuǎn)速雖相等而行程卻又不同的這一運動學(xué)上的矛盾，引起某一驅(qū)動車輪產(chǎn)生滑轉(zhuǎn)或滑移。這不僅會使輪胎過早磨損、無益地消耗功率和燃料及使驅(qū)動車輪軸超載等，還會因為不能按所要求的瞬時中心轉(zhuǎn)向而使操縱性變壞。此外，由于車輪與路面間尤其在轉(zhuǎn)彎時有大的滑轉(zhuǎn)或滑移，易使汽車在轉(zhuǎn)向時失去抗側(cè)滑能力而使穩(wěn)定性變壞。為了消除由于左右車輪在運動學(xué)上的不協(xié)調(diào)而產(chǎn)生的這些弊病， 汽車左右驅(qū)動輪間都裝有差速器，后者保證了汽車驅(qū)動橋兩側(cè)車輪在行程不等時具有以不同速度旋轉(zhuǎn)的特性，從而滿足了汽車行駛運動學(xué)要求。 同樣情況也發(fā)生在多橋驅(qū)動中，前、后驅(qū)動橋之間，中、后驅(qū)動橋之間等 會因車輪滾動半徑不同而導(dǎo)致驅(qū)動橋間的功率循環(huán)，從而使傳動系的載荷增大，損傷其零件，增加輪胎的磨損和燃料的消耗等，因此一些多橋驅(qū)動的汽車上也裝了軸間差速器。 差速器的結(jié)構(gòu)型式選擇，應(yīng)從所設(shè)計汽車的類型及其使用條件出發(fā)，以滿足該型汽車在給定的使用條件下的使用性能要求。 差速器的結(jié)構(gòu)型式有多種。大多數(shù)汽車都屬于公路運輸車輛，對于在公路上和市區(qū)行駛的汽車來說，由于路面較好，各驅(qū)動車輪與路面的附著系數(shù)變化很小，因此幾乎都采用了結(jié)構(gòu)簡單、工作平穩(wěn)、制造方便、用于公路汽車也很可靠的普通對稱式圓錐行星齒輪差速器，作為安裝在左、右驅(qū)動輪間的所謂輪間差速器使用；對于經(jīng)常行駛在泥濘、松軟土路或無路地區(qū)的越野汽車來說，為了防止因某一側(cè)驅(qū)動車輪滑轉(zhuǎn)而陷車，則可采用 防滑差速器。后者又分為強制鎖止式和自鎖式兩類。自鎖式差速器又有多種結(jié)構(gòu)型式的高摩擦式和自由輪式的以及變傳動比式的。- -351．對稱式圓錐行星齒輪差速器普通的對稱式圓錐行星齒輪差速器由差速器左、右殼，2 個半軸齒輪，4個行星齒輪(少數(shù)汽車采用 3 個行星齒輪，小型、微型汽車多采用 2 個行星齒輪)，行星齒輪軸( 不少裝 4 個行星齒輪的差逮器采用十字軸結(jié)構(gòu))，半軸齒輪及行星齒輪墊片等組成。由于其結(jié)構(gòu)簡單、工作平穩(wěn)、制造方便、用在公路汽車上也很可靠等優(yōu)點，最廣泛地用在轎車、客車和各種公路用載貨汽車上．有些越野汽車也采用了這種結(jié)構(gòu)，但用到越野汽車上需要采取防滑措施。例如加進(jìn)摩擦元件以增大其內(nèi)摩擦，提高其鎖緊系數(shù)；或加裝可操縱的、能強制鎖住差速器的裝置-差速鎖等。由于整速器殼是裝在主減速器從動齒輪上，故在確定主減速界從動齒輪尺寸時，應(yīng)考慮差速器的安裝。差速器殼的輪廓尺寸也受到從動齒輪及主動齒輪導(dǎo)向軸承支座的限制。 2．強制鎖止式防滑差速器充分利用牽引力的最簡單的一種方法是在普通的圓錐齒輪差速器上加裝差速鎖，必要時將差速器鎖住。此時左、右驅(qū)動車輪可以傳遞由附著力決定的全部轉(zhuǎn)矩。當(dāng)汽車駛?cè)胼^好的路面時，差速器的鎖止機構(gòu)應(yīng)即時松開，否則將產(chǎn)生與無差速器時一樣的問題，例如使轉(zhuǎn)彎困難、輪胎加速磨損、使傳動系零件過載和消耗過多的功率等。由于上述種種原因，強制鎖住差速器的方法未得到廣泛應(yīng)用。3.自鎖式差速器為了充分利用汽車的牽引力，保證轉(zhuǎn)矩在驅(qū)動車輪間的不等分配以提高抗滑能力，并避免上述強制鎖止式差速器的缺點，創(chuàng)造了各種類型的自鎖式差速器。用以評價自鎖式差速器性能的主要參數(shù)，是它的鎖緊系數(shù)。為了提高汽車的通過性，似乎是鎖緊系數(shù)愈大愈好，但是過大的鎖緊系數(shù)如前所述，不但對汽車轉(zhuǎn)向操縱的輕便靈活性、行駛的穩(wěn)定性、傳動系的載荷、輪胎磨損和燃料消耗等，有不同程度的不良影響，而且無助于進(jìn)一步提高驅(qū)動車輪抗滑能力。因此設(shè)計高通過性汽車差速器時，應(yīng)正確選擇鎖緊系數(shù)值。一般越野汽車的低壓輪胎與地面的附著系數(shù)的最大值為 0.7~0.8(在干燥的柏油或混凝土路面上)，而最小值為 0.1~0.2(在開始溶化的冰上)。可見相差懸殊的附著系數(shù)的最大比值為 8。因此，為了充分利用汽車牽引力，差速器的鎖緊系數(shù) K 實際上選定為 8 就已足夠。- -36而汽車在不好的道路和無路地區(qū)行駛的實踐表明，各驅(qū)動車輪與地面附著系數(shù)不同數(shù)值之比，一般不超過 3~4。因此選取 K＝3~4 是合適的，在這種情況下汽車的通過性可以得到顯著的提高，而其轉(zhuǎn)向操縱等使用性能實際上并不變壞。自鎖式差速器有滑塊-凸輪式、蝸輪式、自由輪式等多種形式。- -37DifferentialAccording to the requirements of vehicle kinematics and the actual wheel, road and the mutual relations between them that in a moving vehicle in the course of the wheel around the same time as a scrolled off the itinerary is often the difference. For example, when turning the wheel outside than the inside of the total trip length. In addition, even if a vehicle traveling straight, also due to wheel around the same time as a scrolled off the surface of the different vertical wave, or a wheel about tire pressure, tire load, tread wear and the different levels, such as manufacturing error factors about different diameter wheel or rolling radius of the wheels do not require the same itinerary ranging. Trip around the wheels in the range of circumstances, if we adopt an overall drive axle vehicles will pass around momentum wheels, the wheels will be driven around because of the speed and although the same itinerary but different in this campaign of the contradictions, have caused a drive wheel to slide or slip. This will not only premature tire wear and not conducive to consumption of power and fuel and to drive axle vehicles such as overloading, but also because they can not according to the requirements of the instantaneous center to manipulation of deterioration. In addition, because the road between the wheel and in particular at a major turning to slide or slip easily in the vehicle to spin when the loss of the ability and stability deteriorate. In order to remove the wheel because of kinematics about the lack of coordination caused by these shortcomings, cars are equipped with about differential between the driving wheel, which guarantee the bridge on both sides of the wheel drive vehicle in the range when a trip to the speed of rotation of different characteristics, so as to meet the requirements of the automobile on kinematics. The same situation also occurred in the bridge drive, before and after the bridge between the driver, during and after the bridge between the drive wheels rolling, and so will lead to different radius of the bridge between the power-driven cycle, thus enabling transmission The load increased, damage its parts, increased tire wear and fuel consumption, some more bridge-driven cars also with the differential between the shaft. The differential structure of choice, should be designed by the type of vehicle and - -38its use conditions, to meet this type of vehicle in a given under the conditions of the use of the use of performance requirements. The differential structure of a variety. Most cars are all road transport vehicles in urban traffic on highways and the automobile, because the roads better, the drive wheel and the road attachment coefficient little change, almost all adopted the simple structure, steady work, Manufacturing convenient for road vehicles are reliable general symmetrical cone planetary gear differential, as installed on the left and right driving wheel of the so-called round of the differential between the use of the regular traffic in the mud, loose dirt roads or areas Another Day The off-road vehicle, in order to prevent side of a car driven roller sports cars to turn depression, can use non-slip differential. The latter is divided into mandatory locking-and-two types of self-locking. Self-locking differential has a variety of types of high-friction-free and the wheel and variable-ratio transmission. 1. Symmetrical cone planetary gear differential General symmetrical cone differential planetary gear differential from the left and right shells, two axle gear, four planetary gear (a small number of cars using three planetary gear, small, micro-car use of two planetary gear), Planetary gear shaft (many with four planetary gear caught for the poor structure of a cross-axis), the axle gear and planetary gear pads, and other components. Because of its simple structure and work steadily to create convenience for use in highway vehicles are very reliable, and other advantages, the most widely used in cars, buses and cars laden with all kinds of highway on. Some off-road vehicles using this structure, but off-road vehicle use on the need to take anti-skid measures. For example, to add friction components in order to increase its internal friction and enhance its locking factor, or the installation of manoeuvrable, the differential can be locked mandatory device - such as differential lock. As for speed the whole shell is installed in the main driven gear reducer, the slowdown is the main sector in determining the size driven gear, the differential should consider the installation. The outline of the differential shell size has been driven gear and active-oriented gear bearing supports the restrictions. 2.Lock-style non-slip differential mandatory Make full use of traction the most simple method is in the ordinary bevel gear - -39differential on the installation of differential lock, if necessary, will be locked differential. At this point the left and right wheel drive transmission can be decided by the adhesion of all torque. When the car into a better road, the differential lock agencies should immediately release, otherwise, they will have no differential with the same problem when, for example, difficult to change, accelerated tire wear so that the transmission parts and overload excessive consumption of power, and so on. As a result of these various reasons, the compulsory lock the differential approach has not been widely used. 3.Self-locking differential To make full use of vehicle traction to ensure that the torque between the drive wheels, ranging from distribution to enhance the ability of anti-sliding, and to avoid the mandatory locking differential for the shortcomings and created all kinds of self-locking differential to evaluate self-locking differential of the main parameters, it is the locking factor. In order to improve the car passed, the greater factor seems to be locking better, but too much of the locking factor as mentioned earlier, not only for the vehicle to manipulate the light flexibility on the stability of the transmission of the load, tire wear and fuel consumption, there are different degrees of adverse effects, but does not help to further enhance the anti-slide wheel drive capability. Thus the design of the car through the high differential, they should correct choice of numerical locking. General cross-country vehicles with low-pressure tires attached to the ground for maximum coefficient of 0.7 to 0.8 (the dry asphalt or coagulating on the road), while the minimum is 0.1 to 0.2 (at the beginning of the melting ice). This shows that the difference between the attachment coefficient for the largest ratio of 8. Therefore, in order to make full use of vehicle traction, the locking differential coefficient K actually selected for the eight is enough. The car in the bad roads and areas.Another day on the practice shows that the drive wheels with the ground attached to different numerical coefficient ratio, generally no more than 3 to 4. So select the K =3 ~ 4 is the appropriate, in which case the adoption of the vehicle can be significantly improved, and its use to control such as performance is not deteriorating.Self-locking differential with the slider - Cam, worm-style, free wheel, and other means.