汽車主減速器設計
汽車主減速器設計,汽車,減速器,設計
本科畢業(yè)設計（論文）
驅(qū)動橋設計
隨著汽車對安全、節(jié)能、環(huán)保的不斷重視，汽車后橋作為整車的一個關鍵部件，其產(chǎn)品的質(zhì)量對整車的安全使用及整車性能的影響是非常大的，因而對汽車后橋進行有效的優(yōu)化設計計算是非常必要的。
驅(qū)動橋處于動力傳動系的末端，其基本功能是增大由傳動軸或變速器傳來的轉(zhuǎn)矩,并將動力合理地分配給左、右驅(qū)動輪，另外還承受作用于路面和車架或車身之間的垂直力力和橫向力。驅(qū)動橋一般由主減速器、差速器、車輪傳動裝置和驅(qū)動橋殼等組成。
驅(qū)動橋作為汽車四大總成之一，它的性能的好壞直接影響整車性能，而對于載重汽車顯得尤為重要。驅(qū)動橋設計應當滿足如下基本要求：
1、符合現(xiàn)代汽車設計的一般理論。
2、外形尺寸要小，保證有必要的離地間隙。
3、合適的主減速比，以保證汽車的動力性和燃料經(jīng)濟性。
4、在各種轉(zhuǎn)速和載荷下具有高的傳動效率。
5、在保證足夠的強度、剛度條件下，力求質(zhì)量小，結(jié)構(gòu)簡單，加工工藝性好，制造容易，拆裝，調(diào)整方便。
6、與懸架導向機構(gòu)運動協(xié)調(diào)，對于轉(zhuǎn)向驅(qū)動橋，還應與轉(zhuǎn)向機構(gòu)運動協(xié)調(diào)。
智能電子技術在汽車上得以推廣使得汽車在安全行駛和其它功能更上一層樓。通過各種傳感器實現(xiàn)自動駕駛。除些之外智能汽車裝備有多種傳感器能充分感知交通設施及環(huán)境的信息并能隨時判斷車輛及駕駛員是否處于危險之中，具備自主尋路、導航、避撞、不停車收費等功能。有效提高運輸過程中的安全，減少駕駛員的操縱疲勞度，提高乘客的舒適度。當然蓄電池是電動汽車的關鍵，電動汽車用的蓄電池主要有：鉛酸蓄電池、鎳鎘蓄電池、鈉硫蓄電池、鈉硫蓄電池、鋰電池、鋅—空氣電池、飛輪電池、燃料電池和太陽能電池等。在諸多種電池中，燃料電池是迄今為止最有希望解決汽車能源短缺問題的動力源。燃料電池具有高效無污染的特性，不同于其他蓄電池，其不需要充電，只要外部不斷地供給燃料，就能連續(xù)穩(wěn)定地發(fā)電。燃料電池汽車(FCEV)具有可與內(nèi)燃機汽車媲美的動力性能，在排放、燃油經(jīng)濟性方面明顯優(yōu)于內(nèi)燃機車輛。
另外，設計必須得考慮所選擇材料的可加工性能。一種材料的可機加工性通常以四種因素的方式定義：
1分的表面光潔性和表面完整性。
2刀具的壽命。
3切削力和功率的需求。
4切屑控制。
以這種方式，好的可機加工性指的是好的表面光潔性和完整性，長的刀具壽命，低的切削力和功率需求。關于切屑控制，細長的卷曲切屑，如果沒有被切割成小片，以在切屑區(qū)變的混亂，纏在一起的方式能夠嚴重的介入剪切工序。
因為剪切工序的復雜屬性，所以很難建立定量地釋義材料的可機加工性的關系。在制造廠里，刀具壽命和表面粗糙度通常被認為是可機加工性中最重要的因素。盡管已不再大量的被使用，近乎準確的機加工率在以下的例子中能夠被看到。
通常，零件的可機加工性能是根據(jù)以下因素來定義的：表面粗糙度，刀具的壽命，切削力和功率的需求以及切屑的控制。材料的可機加工性能不僅取決于起內(nèi)在特性和微觀結(jié)構(gòu)，而且也依賴于工藝參數(shù)的適當選擇與控制。
拖臂懸架
結(jié)合起來的一種行為,semi-trailing-arm落后表現(xiàn)出軸。它是用來驅(qū)動的汽車前面。如果軸經(jīng)驗,它就像一卷懸垂態(tài)的手臂。扭轉(zhuǎn)剛度的摩天大樓,這活象一個stabiliser酒吧。如果兩個輪子的旅行經(jīng)歷相同的懸架(例如在球場的汽車)軸表現(xiàn)得像個拖臂懸架。
梁式軸(Four-Link-Style)
前面的一輛汽車后軸,不必有相同的高度為他們的卷中心。輥軸軸線上,這是經(jīng)過輥子的中心——和后軸,看到前面的圖。
輥軸
如果一個橫向力的重心,導致層(fom)上面的重心軸的卷必須補償片刻所致。由于一些彈簧懸輥。這一刻之間分配方面和后橋有賴于相對彈簧剛度的前面,與后軸,整體側(cè)傾角(這是一樣的,和后軸)取決于總和的懸架剛度(前加上后方)。傳送到地面的瞬間,沒有任何卷的整體車輛通過應用側(cè)向力軸向前滾動的位置(在CG)。(注:如果滾動的軸,剩下的扭矩,CG必須補償汽懸泉會像一輛摩托車內(nèi)傾斜。這一幕的分布與后軸會,計算了
分別計算各軸的位置,by-using相應的axle-using卷中心的一部分的事實,輪軸橫向力所承受的一部分,與正常負荷、輪軸必須隨身攜帶
不同的例子
一個有限的特點,防滑差速器有點不同,不同的風格，一個自鎖裝置。
這個Torsen?風格差異;(從扭矩遙感)行為非常快(并可能嚴厲的)。在較低的輸入扭矩的差動齒輪只是輕輕負載和移動，自由敞開的裝置。隨著力矩和速度起落架網(wǎng)格，大米和兩個輸出軸鎖在一起。扭矩比(high-torque-wheel除以low-torque-wheel)不等,2.5:1 max。7:1,Torsen II的風格，從3:1來1.8:1(根據(jù)齒輪,齒輪表面處理的角度,類型的滾子軸承(平原,…)
達納Trac-Loc?limited-slip差的(見圖)包含一些預緊
通過彈簧離合器片、貝爾維爾)提供了一定的靜態(tài)啟動扭矩已經(jīng)在零輸入扭矩。蜘蛛齒輪,齒輪嚙合側(cè)設計那樣(楔形齒),增加輸入扭矩將增加的負擔,提高離合器盤的鎖軸。
獨立的粘性微分鎖的扭矩,但反應速度與輸出軸之間的差異。包括離合器片沒有機械接觸,但是很緊的間隙,使粘滯摩擦提供扭矩的轉(zhuǎn)讓。注意,粘稠的差距在很光滑,有一定的時間延遲,作為粘度增加與所產(chǎn)生的熱量(指的是特殊的液體是合宜的齒厚)。這使得操作容易使用汽車(雖然可以街是太慢了有些應用)。
Design of driving axle
As the car to safety, energy saving, the constant attention to environmental protection, vehicle after vehicle bridge as a key component, the quality of their products on the safe use of cars and car performance of a very large, so the car after Bridge Effectively optimize the design and calculation is very necessary.
Drive Bridge at the end of powertrain, its basic function is to increase came from the drive shaft or transmission of torque and power reasonably allocated to the left and right driving wheel and also bear in the role of the road and trailers or Body of power between the vertical and horizontal force. Drive from the main bridge general reducer, differential and the wheels, transmission and drive axle components, such as Shell.
Bridge drive a vehicle with one of the four trains, its performance will have a direct impact on vehicle performance, and it is particularly important for the truck. Drive bridge should be designed to meet the following basic requirements:
a) a suitable main slowdown than to ensure that the car from the best power and fuel economy.
b) small form factor to ensure that the necessary ground clearance.
c) transmission gears and other parts of a smooth, noise.
d) in various load and speed of transmission with high efficiency.
e) to ensure adequate strength, stiffness conditions, should strive for the quality of small, in particular the quality of the spring as possible, to improve the car ride.
f) suspension and body-oriented movement coordination, the drive to the bridge, should also be coordinated with the campaign steering mechanism.
g) simple structure, processing technology and good, easy to manufacture, enables easy adjustment..
Intelligent electronic technology in the bus to promote safe driving and that the other functions. The realization of automatic driving through various sensors. Except some smart cars equipped with multiple outside sensors can fully perception of information and traffic facilities and to judge whether the vehicles and drivers in danger, has the independent pathfinding, navigation, avoid bump, no parking fees etc. Function. Effectively improve the safe transport of manipulation, reduce the pilot fatigue, improve passenger comfort. Of course battery electric vehicle is the key, the electric car battery mainly has: the use of lead-acid batteries, nickel cadmium battery, the battery, sodium sulfide sodium sulfide lithium battery, the battery, the battery, the flywheel zinc - air fuel cell and solar battery, the battery. In many kind of cells, the fuel cell is by far the most want to solve the problem of energy shortage car. Fuel cells have high pollution characteristics, different from other battery, the battery, need not only external constantly supply of fuel and electricity can continuously steadily. Fuel cell vehicles (FCEV) can be matched with the car engine performance and fuel economy and emission in the aspects of superior internal-combustion vehicles.
Keyword: drive axle differential bridge reducer Bridge shell
This is an ANSYS optimum design for driving axle housing of a off-road vehicle.
Firstly, the author established a three-dimensional model of the driving axle. States of stress in different working conditions were analyzed. Furthermore, the maximum pressure of driving axle was achieved.
And then, the three-dimensional model was imported into ANSYS, with some other manipulations, such as meshing, adding degree of freedom, applying surface loads, etc.
States of stress of driving axle were calculated with the results exported.
Finally, this paper carried out the optimum design according to the target of minimizing the qualitative properties and homogenizing the distribution of stresses. The
Confirmatory analysis showed that this design measured up to the engineering requirement.
MACHINABILITY
The machinability of a material usually defined in terms of four factors:
1、 Surface finish and integrity of the machined part;
2、 Tool life obtained;
3、 Force and power requirements;
4、 Chip control.
Thus, good machinability good surface finish and integrity, long tool life, and low force And power requirements. As for chip control, long and thin (stringy) cured chips, if not broken up, can severely interfere with the cutting operation by becoming entangled in the cutting zone.
Because of the complex nature of cutting operations, it is difficult to establish relationships that quantitatively define the machinability of a material. In manufacturing plants, tool life and surface roughness are generally considered to be the most important factors in machinability. Although not used much any more, approximate machinability ratings are available in the example below.
SUMMARY
Machinability is usually defined in terms of surface finish, tool life, force and power requirements, and chip control. Machinability of materials depends not only on their intrinsic properties and microstructure, but also on proper selection and control of process variables.
A combination of trailing- and semi-trailing-arm behaviour shows the following axis. It is used for front driven cars only. If the axle experiences roll, it behaves like a semi-trailing arm. The torsional stiffness counteracts the roll, by this acting like a stabiliser bar. If both wheels experience the same suspension travel (e.g. during pitch of the car) the axle behaves like a trailing arm suspension.
Beam Type Axle (Four-Link-Style)
Front- and rear-axle of a car needn't have the same hight for their roll center. The roll
axis is that axis, that goes through the roll center of front- and rear-axle, see following
drawing:
Roll Axis
If a lateral force is applied at the center of gravity, the moment resulting fom the hight of
the center of gravity above the roll axis has to be compensated by a moment caused by
the suspension springs due to some roll. The distribution of this moment between front-
and rear axle depends on the relative spring stiffness of front- and rear-axle, the overall
roll angle (which is the same for front- and rear-axle) depends on the sum of the suspension stiffness (front plus rear).
The moment transmitted to the ground without any roll for the overall vehicle is given by
the applied lateral force times the roll axis hight (at the position of CG). (Remark: If the
roll axis is above the CG, the remaining torque that has to be compensated by the
suspension springs would make the car lean inside like a motorcycle!).
The distribution of this moment between front- and rear-axle can be calculated by
calculating each axle seperately, by-using the position of the roll center of the corresponding axle-using the fact that the part of lateral force, that the axle has to carry, corresponds to the part of the normal load, the axle has to carry
Differential Examples
The characteristics of a limited slip differential are a little bit different for different styles
of a self-locking device.
The Torsen? style differentials (from TORque SENsing) act very fast (and possibly
harsh). Under low input torque the differential gears are only lightly loaded and move
freely like an open device. With increasing torque (and speed) the gear meshes are
loaded up and the two output shafts are locked together. The torque ratio (high-torque-wheel divided by low-torque-wheel) varies from max. 7:1 to 2.5:1, for the Torsen II style
from 3:1 to 1.8:1 (depending on gear angles, gear surface treatment, type of
bearing(plain, roller...)
The Dana Trac-Loc? limited-slip differential (see picture below) contains some preloaded
(by Belleville springs) clutch plates, which provide a certain static breakout torque
already at zero input torque. The spider gear and side gear mesh are designed in that way (with wedge-shaped gear teeth), that increasing input torque will increase the load
on the clutch plates, by this increasing the locking of the axle.
Dana Trac-Loc? limited-slip differential
The viscous differential locks independent of of torques, but reacts to the speed
differences between the output shafts. The contained clutch plates have no mechanical
contact, but very tight clearances, so that the viscous friction provides the torque
transfer. Note that viscous differentials set in very smooth, and with a certain time delay, as the
viscosity increases with the generated heat (means the special fluid is becoming
'thicker'). This makes the handling easier for street use cars (while may be too slow for
some racing applications).
9
收藏