附 錄 附錄 A Drive axle/differential All vehicles have some type of drive axle/differential assembly incorporated into the driveline. Whether it is front, rear or four wheel drive, differentials are necessary for the smooth application of engine power to the road. Powerflow The drive axle must transmit power through a 90 angle. The flow of power in conventional front engine/rear wheel drive vehicles moves from the engine to the drive axle in approximately a straight line. However, at the drive axle, the power must be turned at right angles (from the line of the driveshaft) and directed to the drive wheels. This is accomplished by a pinion drive gear, which turns a circular ring gear. The ring gear is attached to a differential housing, containing a set of smaller gears that are splined to the inner end of each axle shaft. As the housing is rotated, the internal differential gears turn the axle shafts, which are also attached to the drive wheels. Fig 1 Drive axle Rear-wheel drive Rear-wheel-drive vehicles are mostly trucks, very large sedans and many sports car and coupe models. The typical rear wheel drive vehicle uses a front mounted engine and transmission assemblies with a driveshaft coupling the transmission to the rear drive axle. Drive in through the layout of the bridge, the bridge drive shaft arranged vertically in the same vertical plane, and not the drive axle shaft, respectively, in their own sub-actuator with a direct connection, but the actuator is located at the front or the back of the adjacent shaft of the two bridges is arranged in series. Vehicle before and after the two ends of the driving force of the drive axle, is the sub-actuator and the transmission through the middle of the bridge. The advantage is not only a reduction of the number of drive shaft, and raise the driving axle of the common parts of each other, and to simplify the structure, reduces the volume and quality. Fig 2 Rear-wheel-drive axle Some vehicles do not follow this typical example. Such as the older Porsche or Volkswagen vehicles which were rear engine, rear drive. These vehicles use a rear mounted transaxle with halfshafts connected to the drive wheels. Also, some vehicles were produced with a front engine, rear transaxle setup with a driveshaft connecting the engine to the transaxle, and halfshafts linking the transaxle to the drive wheels. Differential operation In order to remove the wheel around in the kinematics due to the lack of co-ordination about the wheel diameter arising from a different or the same rolling radius of wheel travel required, inter-wheel motor vehicles are equipped with about differential, the latter to ensure that the car driver Bridge on both sides of the wheel when in range with a trip to the characteristics of rotating at different speeds to meet the requirements of the vehicle kinematics. Fig 3 Principle of differential The accompanying illustration has been provided to help understand how this occurs. 1.The drive pinion, which is turned by the driveshaft, turns the ring gear. 2.The ring gear, which is attached to the differential case, turns the case. 3.The pinion shaft, located in a bore in the differential case, is at right angles to the axle shafts and turns with the case. 4.The differential pinion (drive) gears are mounted on the pinion shaft and rotate with the shaft . 5.Differential side gears (driven gears) are meshed with the pinion gears and turn with the differential housing and ring gear as a unit. 6.The side gears are splined to the inner ends of the axle shafts and rotate the shafts as the housing turns. 7.When both wheels have equal traction, the pinion gears do not rotate on the pinion shaft, since the input force of the pinion gears is divided equally between the two side gears. 8.When it is necessary to turn a corner, the differential gearing becomes effective and allows the axle shafts to rotate at different speeds . Open-wheel differential on each general use the same amount of torque. To determine the size of the wheel torque to bear two factors: equipment and friction. In dry conditions, when a lot of friction, the wheel bearing torque by engine size and gear restrictions are hours in the friction (such as driving on ice), is restricted to a maximum torque, so that vehicles will not spin round. So even if the car can produce more torque, but also need to have sufficient traction to transfer torque to the ground. If you increase the throttle after the wheels slip, it will only make the wheels spin faster. Fig 4 Conventional differential Limited-slip and locking differential operation Fig 5 Limited-slip differential Differential settlement of a car in the uneven road surface and steering wheel-driven speed at about the different requirements； but is followed by the existence of differential in the side car wheel skid can not be effective when the power transmission, that is, the wheel slip can not produce the driving force, rather than spin the wheel and does not have enough torque. Good non-slip differential settlement of the car wheels skid on the side of the power transmission when the issue, that is, locking differential, so that no longer serve a useful differential right and left sides of the wheel can be the same torque. Limited-slip and locking differential operation can be divided into two major categories： (1) mandatory locking type in ordinary differential locking enforcement agencies to increase, when the side of the wheel skid occurs, the driver can be electric, pneumatic or mechanical means to manipulate the locking body meshing sets of DIP Shell will be with the axle differential lock into one, thus the temporary loss of differential role. Relatively simple structure in this way, but it must be operated by the driver, and good roads to stop locking and restore the role of differential. (2) self-locking differential installed in the oil viscosity or friction clutch coupling, when the side of the wheel skid occurs when both sides of the axle speed difference there, coupling or clutch friction resistance on the automatic, to make certain the other side of the wheel drive torque and the car continued to travel. When there is no speed difference on both sides of the wheel, the frictional resistance disappeared, the role of automatic restoration of differentials. More complicated structure in this way, but do not require drivers to operate. Has been increasingly applied in the car. About non-slip differential, not only used for the differential between the wheels, but also for all-wheel drive vehicle inter-axle differential/. Gear ratio The drive axle of a vehicle is said to have a certain axle ratio. This number (usually a whole number and a decimal fraction) is actually a comparison of the number of gear teeth on the ring gear and the pinion gear. For example, a 4.11 rear means that theoretically, there are 4.11 teeth on the ring gear for each tooth on the pinion gear or, put another way, the driveshaft must turn 4.11 times to turn the wheels once. The role of the final drive is to reduce the speed from the drive shaft, thereby increasing the torque. Lord of the reduction ratio reducer, a driving force for car performance and fuel economy have a greater impact. In general, the more reduction ratio the greater the acceleration and climbing ability, and relatively poor fuel economy. However, if it is too large, it can not play the full power of the engine to achieve the proper speed. The main reduction ratio is more Smaller ， the speed is higher, fuel economy is better, but the acceleration and climbing ability will be poor. 附 錄 B 驅動橋和差速器 所有的汽車都裝有不同類型的驅動橋和差速器來驅動汽車行駛。無論是前驅汽車，后驅汽車還是四輪驅動的汽車，對于將發動機的動力轉化到車輪上差速器都是不可缺少的部件。 動力的傳遞 驅動橋必須把發動機的動力轉一個直角后傳遞出去，但人對于前輪驅動汽車發動機輸出的轉矩與主減速器是在同一直線上的，但是發動機前置的后輪驅動的汽車發動機的動力必須以正確 的角度傳遞出去，來驅動車輪。 圖中所示是齒輪驅動的過程，即由一個相對小的齒輪驅動一個大齒輪（主動齒輪和從動齒輪），從動錐齒輪和差速器殼連接在一起，在半軸的根部有一對帶有內花鍵的半軸齒輪，半軸齒輪和半軸通過花鍵來連接在一起。當差速器殼旋轉時，就驅動內部的半齒輪轉動從而使半軸轉動，將轉矩傳給車輪。 后驅動橋 后輪驅動的車輛大多是卡車，大型轎車和大部分跑車。典型的后輪驅動的車輛使用前置發動機和變速箱總成將轉矩傳輸到后輪驅動橋。多驅動橋汽車中，在貫通式驅動橋的布置中，各橋的傳動軸布置在同一縱向鉛垂平面內，并且各驅動橋不是分別用自己的傳動軸與分動器直接聯接，而是位于分動器前面的或后面的各相鄰兩橋的傳動軸，是串聯布置的。汽車前后兩端的驅動橋的動力，是經分動器并貫通中間橋而傳遞的。其優點是，不僅減少了傳動軸的數量，而且提高了各驅動橋零件的相互通用性，并且簡化了結構、減小了體積和質量。 一些車輛不是這個典型的例子。如老式的保時捷或大眾汽車引擎在汽車后面，是后輪驅動。這些車輛使用的后方安裝驅動橋與半軸 來 驅動車輪。另外，一些車輛是前置引擎，后橋與傳動軸連接發動機 來 驅動車輪。 差速器 為了消除由于左右車輪在運動學上的不協調而產生左 右車輪外徑不同或滾動半徑不相等而要求車輪行程，汽車左右驅動輪間都裝有差速器，后者保證了汽車驅動橋兩側車輪在行程不等時具有以不同速度旋轉的特性，從而滿足了汽車行駛運動學要求。 如圖所示說明了其工作情況 1. 主動齒輪轉動，從而驅動 從動 齒輪 。 2. 從動齒輪將轉矩作用于差速器殼，使其轉動。 3. 位于差速器殼中的行星齒輪以適當的角度和半軸齒輪接觸， 并隨的差速器殼轉動。 4. 行星齒輪（驅動齒輪）和十字軸連接，和十字軸一起轉動。 5. 半軸齒輪（被驅動齒輪）和行星齒輪嚙合并且和從動齒輪及差速器殼作為一個整體一起轉動。 6. 半軸齒輪的內花鍵和半軸端 部餓花鍵接在一起隨著差速殼一起轉動。 7. 當兩側車輪轉速相同時，行星齒輪和半軸齒輪無相對運動，左右齒輪力矩平均分配。 8. 當汽車轉彎時差速器開始起作用，是兩側的半軸以不同的轉速旋轉。 開式差速器 對每個車輪一般使用相同量的扭矩。確定車輪承受的扭矩大小的因素有兩個：設備和摩擦力。在干燥的條件下，當摩擦力很大時，車輪承受的扭矩大小受發動機和擋位的限制，在摩擦力很小時（如在冰上行駛），限制為最大扭矩，從而使車輪不會打滑。所以，即使汽車可以產生較大扭矩，也需要足夠