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附錄1
驅(qū)動(dòng)橋橋殼是汽車上的主要零件之一,非斷開式驅(qū)動(dòng)橋的橋殼起著支承汽車荷重的作用,并將載荷傳給車輪.作用在驅(qū)動(dòng)車輪上的牽引力,制動(dòng)力、側(cè)向力和垂向力也是經(jīng)過橋殼傳到懸掛及車架或車廂上。因此橋殼既是承載件又是傳力件,同時(shí)它又是主減速器、差速器及驅(qū)動(dòng)車輪傳動(dòng)裝置(如半軸)的外殼。
在汽車行駛過程中,橋殼承受繁重的載荷,設(shè)計(jì)時(shí)必須考慮在動(dòng)載荷下橋殼有足夠的強(qiáng)度和剛度。為了減小汽車的簧下質(zhì)量以利于降低動(dòng)載荷、提高汽車的行駛平順性,在保證強(qiáng)度和剛度的前提下應(yīng)力求減小橋殼的質(zhì)量.橋殼還應(yīng)結(jié)構(gòu)簡單、制造方便以利于降低成本。其結(jié)構(gòu)還應(yīng)保證主減速器的拆裝、調(diào)整、維修和保養(yǎng)方便。在選擇橋殼的結(jié)構(gòu)型式時(shí),還應(yīng)考慮汽車的類型、使用要求、制造條件、材料供應(yīng)等。
橋殼的結(jié)構(gòu)型式
橋殼的結(jié)構(gòu)型式大致分為可分式、整體式。
可分式橋殼
可分式橋殼的整個(gè)橋殼由一個(gè)垂直接合面分為左右兩部分,每一部分均由一個(gè)鑄件殼體和一個(gè)壓入其外端的半軸套管組成。半軸套管與殼體用鉚釘聯(lián)接。在裝配主減速器及差速器后左右兩半橋殼是通過在中央接合面處的一圈螺栓聯(lián)成一個(gè)整體。其特點(diǎn)是橋殼制造工藝簡單、主減速器軸承支承剛度好。但對主減速器的裝配、調(diào)整及維修都很不方便,橋殼的強(qiáng)度和剛度也比較低。過去這種所謂兩段可分式橋殼見于輕型汽車,由于上述缺點(diǎn)現(xiàn)已很少采用。
整體式橋殼
整體式橋殼的特點(diǎn)是將整個(gè)橋殼制成一個(gè)整體,橋殼猶如一整體的空心粱,其強(qiáng)度及剛度都比較好。且橋殼與主減速器殼分作兩體,主減速器齒輪及差速器均裝在獨(dú)立的主減速殼里,構(gòu)成單獨(dú)的總成,調(diào)整好以后再由橋殼中部前面裝入橋殼內(nèi),并與橋殼用螺栓固定在一起。使主減速器和差速器的拆裝、調(diào)整、維修、保養(yǎng)等都十分方便。
整體式橋殼按其制造工藝的不同又可分為鑄造整體式、鋼板沖壓焊接式和鋼管擴(kuò)張成形式三種。
驅(qū)動(dòng)橋處于動(dòng)力傳動(dòng)系的末端,其基本功能是增大由傳動(dòng)軸或變速器傳來的轉(zhuǎn)矩,并將動(dòng)力合理地分配給左、右驅(qū)動(dòng)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(dòng)橋一般由主減速器、差速器、車輪傳動(dòng)裝置和驅(qū)動(dòng)橋殼等組成。
驅(qū)動(dòng)橋設(shè)計(jì)應(yīng)當(dāng)滿足如下基本要求:
(a)所選擇的主減速比應(yīng)能保證汽車具有最佳的動(dòng)力性和燃料經(jīng)濟(jì)性。
(b)外形尺寸要小,保證有必要的離地間隙。
(c)齒輪及其它傳動(dòng)件工作平穩(wěn),噪聲小。
(d)在各種轉(zhuǎn)速和載荷下具有高的傳動(dòng)效率。
(e)在保證足夠的強(qiáng)度、剛度條件下,應(yīng)力求質(zhì)量小,尤其是簧下質(zhì)量應(yīng)盡量小,以改善汽車平順性。
(f)與懸架導(dǎo)向機(jī)構(gòu)運(yùn)動(dòng)協(xié)調(diào),對于轉(zhuǎn)向驅(qū)動(dòng)橋,還應(yīng)與轉(zhuǎn)向機(jī)構(gòu)運(yùn)動(dòng)協(xié)調(diào)。
(g)結(jié)構(gòu)簡單,加工工藝性好,制造容易,拆裝,調(diào)整方便。
驅(qū)動(dòng)橋的結(jié)構(gòu)型式按工作特性分,可以歸并為兩大類,即非斷開式驅(qū)動(dòng)橋和斷開式驅(qū)動(dòng)橋。當(dāng)驅(qū)動(dòng)車輪采用非獨(dú)立懸架時(shí),應(yīng)該選用非斷開式驅(qū)動(dòng)橋;當(dāng)驅(qū)動(dòng)車輪采用獨(dú)立懸架時(shí),則應(yīng)該選用斷開式驅(qū)動(dòng)橋。因此,前者又稱為非獨(dú)立懸架驅(qū)動(dòng)橋;后者稱為獨(dú)立懸架驅(qū)動(dòng)橋。獨(dú)立懸架驅(qū)動(dòng)橋結(jié)構(gòu)叫復(fù)雜,但可以大大提高汽車在不平路面上的行駛平順性。
非斷開式驅(qū)動(dòng)橋
普通非斷開式驅(qū)動(dòng)橋,由于結(jié)構(gòu)簡單、造價(jià)低廉、工作可靠,廣泛用在各種載貨汽車、客車和公共汽車上,在多數(shù)的越野汽車和部分轎車上也采用這種結(jié)構(gòu)。他們的具體結(jié)構(gòu)、特別是橋殼結(jié)構(gòu)雖然各不相同,但是有一個(gè)共同特點(diǎn),即橋殼是一根支承在左右驅(qū)動(dòng)車輪上的剛性空心梁,齒輪及半軸等傳動(dòng)部件安裝在其中。這時(shí)整個(gè)驅(qū)動(dòng)橋、驅(qū)動(dòng)車輪及部分傳動(dòng)軸均屬于簧下質(zhì)量,汽車簧下質(zhì)量較大,這是它的一個(gè)缺點(diǎn)。
驅(qū)動(dòng)橋的輪廓尺寸主要取決于主減速器的型式。在汽車輪胎尺寸和驅(qū)動(dòng)橋下的最小離地間隙已經(jīng)確定的情況下,也就限定了主減速器從動(dòng)齒輪直徑的尺寸。在給定速比的條件下,如果單級主減速器不能滿足離地間隙要求,可該用雙級結(jié)構(gòu)。在雙級主減速器中,通常把兩級減速器齒輪放在一個(gè)主減速器殼體內(nèi),也可以將第二級減速齒輪作為輪邊減速器。對于輪邊減速器:越野汽車為了提高離地間隙,可以將一對圓柱齒輪構(gòu)成的輪邊減速器的主動(dòng)齒輪置于其從動(dòng)齒輪的垂直上方;公共汽車為了降低汽車的質(zhì)心高度和車廂地板高度,以提高穩(wěn)定性和乘客上下車的方便,可將輪邊減速器的主動(dòng)齒輪置于其從動(dòng)齒輪的垂直下方;有些雙層公共汽車為了進(jìn)一步降低車廂地板高度,在采用圓柱齒輪輪邊減速器的同時(shí),將主減速器及差速器總成也移到一個(gè)驅(qū)動(dòng)車輪的旁邊。
在少數(shù)具有高速發(fā)動(dòng)機(jī)的大型公共汽車、多橋驅(qū)動(dòng)汽車和超重型載貨汽車上,有時(shí)采用蝸輪式主減速器,它不僅具有在質(zhì)量小、尺寸緊湊的情況下可以得到大的傳動(dòng)比以及工作平滑無聲的優(yōu)點(diǎn),而且對汽車的總體布置很方便。
斷開式驅(qū)動(dòng)橋
斷開式驅(qū)動(dòng)橋區(qū)別于非斷開式驅(qū)動(dòng)橋的明顯特點(diǎn)在于前者沒有一個(gè)連接左右驅(qū)動(dòng)車輪的剛性整體外殼或梁。斷開式驅(qū)動(dòng)橋的橋殼是分段的,并且彼此之間可以做相對運(yùn)動(dòng),所以這種橋稱為斷開式的。另外,它又總是與獨(dú)立懸掛相匹配,故又稱為獨(dú)立懸掛驅(qū)動(dòng)橋。這種橋的中段,主減速器及差速器等是懸置在車架橫粱或車廂底板上,或與脊梁式車架相聯(lián)。主減速器、差速器與傳動(dòng)軸及一部分驅(qū)動(dòng)車輪傳動(dòng)裝置的質(zhì)量均為簧上質(zhì)量。兩側(cè)的驅(qū)動(dòng)車輪由于采用獨(dú)立懸掛則可以彼此致立地相對于車架或車廂作上下擺動(dòng),相應(yīng)地就要求驅(qū)動(dòng)車輪的傳動(dòng)裝置及其外殼或套管作相應(yīng)擺動(dòng)。
汽車懸掛總成的類型及其彈性元件與減振裝置的工作特性是決定汽車行駛平順性的主要因素,而汽車簧下部分質(zhì)量的大小,對其平順性也有顯著的影響。斷開式驅(qū)動(dòng)橋的簧下質(zhì)量較小,又與獨(dú)立懸掛相配合,致使驅(qū)動(dòng)車輪與地面的接觸情況及對各種地形的適應(yīng)性比較好,由此可大大地減小汽車在不平路面上行駛時(shí)的振動(dòng)和車廂傾斜,提高汽車的行駛平順性和平均行駛速度,減小車輪和車橋上的動(dòng)載荷及零件的損壞,提高其可靠性及使用壽命。但是,由于斷開式驅(qū)動(dòng)橋及與其相配的獨(dú)立懸掛的結(jié)構(gòu)復(fù)雜,故這種結(jié)構(gòu)主要見于對行駛平順性要求較高的一部分轎車及一些越野汽車上,且后者多屬于輕型以下的越野汽車或多橋驅(qū)動(dòng)的重型越野汽車。
多橋驅(qū)動(dòng)的布置
為了提高裝載量和通過性,有些重型汽車及全部中型以上的越野汽車都是采用多橋驅(qū)動(dòng),常采用的有4×4、6×6、8×8等驅(qū)動(dòng)型式。在多橋驅(qū)動(dòng)的情況下,動(dòng)力經(jīng)分動(dòng)器傳給各驅(qū)動(dòng)橋的方式有兩種。相應(yīng)這兩種動(dòng)力傳遞方式,多橋驅(qū)動(dòng)汽車各驅(qū)動(dòng)橋的布置型式分為非貫通式與貫通式。前者為了把動(dòng)力經(jīng)分動(dòng)器傳給各驅(qū)動(dòng)橋,需分別由分動(dòng)器經(jīng)各驅(qū)動(dòng)橋自己專用的傳動(dòng)軸傳遞動(dòng)力,這樣不僅使傳動(dòng)軸的數(shù)量增多,且造成各驅(qū)動(dòng)橋的零件特別是橋殼、半軸等主要零件不能通用。而對8×8汽車來說,這種非貫通式驅(qū)動(dòng)橋就更不適宜,也難于布置了。
為了解決上述問題,現(xiàn)代多橋驅(qū)動(dòng)汽車都是采用貫通式驅(qū)動(dòng)橋的布置型式。
在貫通式驅(qū)動(dòng)橋的布置中,各橋的傳動(dòng)軸布置在同一縱向鉛垂平面內(nèi),并且各驅(qū)動(dòng)橋不是分別用自己的傳動(dòng)軸與分動(dòng)器直接聯(lián)接,而是位于分動(dòng)器前面的或后面的各相鄰兩橋的傳動(dòng)軸,是串聯(lián)布置的。汽車前后兩端的驅(qū)動(dòng)橋的動(dòng)力,是經(jīng)分動(dòng)器并貫通中間橋而傳遞的。其優(yōu)點(diǎn)是,不僅減少了傳動(dòng)軸的數(shù)量,而且提高了各驅(qū)動(dòng)橋零件的相互通用性,并且簡化了結(jié)構(gòu)、減小了體積和質(zhì)量。這對于汽車的設(shè)計(jì)(如汽車的變型)、制造和維修,都帶來方便。
由于非斷開式驅(qū)動(dòng)橋結(jié)構(gòu)簡單、造價(jià)低廉、工作可靠,查閱資料,可參照國內(nèi)相關(guān)貨車的設(shè)計(jì)。
附錄2
Bridge-driven car shell is one of the main parts, non-drive off-shell bridge played a supporting role in the automotive load and load to the wheels. In the role of the drive wheels on the traction, braking force, lateral and vertical forces also spread to fly through the bridge and the shell or inside the frame. Therefore, the bridge carrying both pieces of shell-edge thing is, at the same time it is also the main reducer, and differential wheel drive transmission (such as the axle) of the shell.
In the car, the axle housing to bear the heavy load, the design must take into account the dynamic load under the axle housing have enough strength and stiffness. In order to reduce the spring under the car of lower quality in order to facilitate dynamic load, and improve the car's running smoothly, while ensuring the strength and stiffness on the premise of the bridge should seek to reduce the quality of the shell. Shell structure of the bridge should be simple and easy to create the benefit of lower costs. It should also ensure that the structure of the main reducer of disassembly, adjustment, repair and maintenance easy. Bridge in the selection of the shell structure, should also be given to the type of car, asked to use, manufacture, supply materials and so on.
A bridge of the shell structure
Bridge of the shell structure can be roughly divided into type
There are bridge-shell
There are bridge-shell as a whole from the shell of a bridge into the vertical joints around two parts, each part by the casting of a shell into the outside pressure and a side of the axle casing components. Half shell casing and connected with rivets. In the main reducer, and differential assembly after about two half-bridge through the shell in the joints of the Central Office of the bolt circle into a whole. It features a simple bridge shell manufacturing process, the main reducer bearing stiffness well. But the main reducer of the assembly, adjustment and maintenance are inconvenient, the bridge shell strength and stiffness will be lower. In the past the so-called two-axle housing can be found in the car light, as a result of these shortcomings is now rarely used.
Whole-axle housin
Bridge-shell as a whole is characterized by the entire bridge made of a shell as a whole, the bridge is like a shell of the hollow beam as a whole, its strength and stiffness than good. Bridge and the shell and the shell will be divided into two main reducer, the main reducer, and differential gears are mounted on the main independent slowdown shell, constitute a separate assembly, later adjusted by the bridge in front of the shell in the central bridge into the shell , And with the axle housing fixed together with bolts. It enables a reducer, and differential of disassembly, adjustment, repair, maintenance and so on is very convenient.
Bridge-shell as a whole according to their different manufacturing process can be divided into a whole-casting, stamping steel plates welded steel pipe and the expansion into three forms.
Bridge drive powertrain in the end, its basic function is to increase the transmission shaft or transmission from the torque and power reasonably allocated to the left and right wheel also bear on the role of road and the frame or body Between vertical and horizontal force strength. Driven by the main bridge in general reducer, and differential, gear wheels and drive axle housing component, and so on.
Drive bridge should be designed to meet the basic requirements are as follows:
(a) choice of the main reduction ratio should be able to ensure the car has the best power and fuel economy.
(b) smaller size, it is necessary to ensure that the ground clearance.
(c) transmission gears and other pieces of work in a smooth, small noise.
(d) in a variety of speed and load with a high transmission efficiency.
(e) to ensure sufficient strength, rigidity conditions, the quality should be as small, especially the quality of the next spring should be small in order to improve the car ride.
(f)-oriented suspension and body movement coordination, the drive to the bridge, but also with the agency to coordinate movement.
(g) simple structure, good process and create easy disassembly, easy adjustment.
Drive bridge structure in accordance with characteristics of the work, can be grouped into two broad categories, namely non-drive off the bridge and drive off the bridge. When the drive wheel of a non-independent suspension, the non-selection should be off-drive axle; when the drive wheel independent suspension, the choice should be off-drive axle. As a result, the former driver, also known as non-independent suspension bridge; the latter known as the independent suspension bridge driver. Independent suspension bridge structure called complex drive, but will be much more uneven in the car traveling on the road ride comfort.
Non-drive axle disconnect
General non-drive off the bridge, because it is simple, low-cost, reliable, widely used in a variety of truck, bus and a bus, in most of the off-road cars and car parts is also using this structure. Details of their structure, in particular, the shell structure of the bridge although different, but there is a common feature of the bridge is a shell around the drive wheel bearing on the rigid hollow beams, such as transmission gears and axle components to install it. At this time the entire drive axle, wheel and drive shaft are part of the quality of the next spring, next spring the quality of the larger car, which is one of its shortcomings.
Bridge drive size depends largely on the outline of the main type of reducer. In the tire size and drive under the bridge minimum ground clearance have been identified, will be limited to the main driven gear reducer diameter size. In a given ratio of the conditions, if the single-stage main reducer not meet the requirements of ground clearance, with the two-level structure. In the main two-stage reducer, usually two-stage gear reducer in a shell of the main reducer, can also slow down in the second grade as a round edge gear reducer. The round side reducer: off-road vehicle in order to improve the ground clearance, can constitute a pair of cylindrical gear wheel of the gear reducer at the top of the vertical driven gear; bus in order to reduce the vehicle's center of mass and a high degree of deck A high degree of order to enhance the stability and convenience of the passengers get off, can be round edge of the gear reducer at the bottom of the vertical driven gear; some double-decker bus in order to further reduce the deck height, cylinder gear used in the round edge Reducer, the main reducer, and differential assembly also moved to a wheel next to the driver.
In a small number of high-speed engine with a large bus, Bridge Multi-drive cars and super-heavy-duty truck, sometimes using the main worm-reducer, which not only has the quality in a small, compact size of the case could be a big transmission ratio, as well as the work of Smooth silent advantages, but also to the overall layout of the car easily.
Drive-off bridge
Off-drive off the bridge from the non-drive axle of the obvious characteristics is that the former do not have a connection about the drive wheels or beam rigid shell as a whole. Drive off-shell bridge is a section, and each other can do relative motion, such as the bridge-off. In addition, it is always with the independent match suspension, it is also known as the independent suspension bridge driver. This bridge in the middle of the main reducer, and differential, and so is mounting in the frame beams inside or on the floor or backbone frame-linked. The main reducer, and differential part of the drive shaft and the quality of the gear wheels are on the quality of the spring. Both sides of the drive wheel independent suspension as a result can be caused by site as opposed to one another or inside the frame for swinging up and down, and accordingly on the request of the gear wheel drive and its shell casing or swing accordingly.
Flying car assembly and its flexibility in the type of device components and vibration characteristics of the work is to determine a car ride a major factor, and the spring under the car the size of some of the quality of its ride quality is also significant. Off-drive axle of the quality of the spring under the smaller, independent suspension with the match, with the result that drive the wheels on the ground and contacts of all kinds of terrain and better adaptability, which can greatly reduce the car in the uneven pavement When traveling on the train vibration and tilt to improve vehicle ride and average speed, and reduce the wheel of Axle Load and move on the part of the damage and improve the reliability and service life. However, due to off-drive axle and independent suspension of the match with the structure of the complex, and they were mainly observed in the structure of the smooth running of the higher part of the car and a number of off-road vehicle, and the latter belongs to light more of the following off-road vehicle Bridge or drive the heavy-duty off-road vehicle.
Multi-Bridge-driven layout
In order to improve the loading and through, and some heavy-duty vehicles and medium-sized all over the off-road vehicle and are based on the multi-bridge driver, there is often used in 4 × 4,6 × 6,8 × 8, and other types of drivers. In the multi-bridge drivers, power points as actuators to drive the bridge in two ways. The two corresponding power transfer mode, multi-drive vehicle bridge the drive axle of the type of layout is divided into non-through-and through. In order to power by the former sub-actuator to the drive axle, respectively, to be divided by the actuator through the drive axle own dedicated power transmission shaft, so that not only the increase in the number of drive shaft and caused the driver of the bridge parts in particular Shell Bridge, the main axle, and other parts can not be universal. The 8 × 8 on the car, this non-drive-through is even more inappropriate for the bridge, a difficult layout.
In order to address these problems, and more modern bridges are built on a car driving through the drive-type layout of the bridge.
In the drive-through layout of the bridge, the bridge of the vertical shaft arranged in the same vertical plane and drive the bridge were not Shaft with their own sub-actuator directly connected, but located at the front of the actuator or Behind the bridge of the two adjacent shaft, the layout of the series is. Before and after the driver of the car at both ends of the bridge's driving force is divided by the actuator and through the middle of the bridge and pass. The advantage is not only a reduction of the number of drive shaft, but the driver raised the bridge parts commonality with each other and to simplify the structure, reducing the size and quality. This car's design (such as car variant), manufacturing and maintenance, are convenient.
Due to the non-drive off the bridge structure is simple, low-cost, reliable access to information relevant in the light truck designs.
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哈爾濱工業(yè)大學(xué)華德應(yīng)用技術(shù)學(xué)院畢業(yè)設(shè)計(jì)(論文) I 摘要 驅(qū)動(dòng)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。當(dāng)采用大功率發(fā)動(dòng)機(jī)輸出大的轉(zhuǎn)矩以滿足 目前載重汽車的快速、重載的高效率、高效益的需要時(shí),必須要搭配一個(gè) 高效、可靠的驅(qū)動(dòng)橋。所以采用傳動(dòng)效率高的雙級減速驅(qū)動(dòng)橋已成為未來 重載汽車的發(fā)展方向。 本文參照傳統(tǒng)驅(qū)動(dòng)橋的設(shè)計(jì)方法進(jìn)行了載重汽車驅(qū)動(dòng)橋的設(shè)計(jì)。本文 首先確定主要部件的結(jié)構(gòu)型式和主要設(shè)計(jì)參數(shù);然后參考類似驅(qū)動(dòng)橋的結(jié) 構(gòu),確定出總體設(shè)計(jì)方案;最后對主,從動(dòng)錐齒輪,差速器圓錐行星齒輪, 半軸齒輪,全浮式半軸和整體式橋殼的強(qiáng)度進(jìn)行校核以及對支承軸承進(jìn)行 了壽命校核。本文不是采用傳統(tǒng)的雙曲面錐齒輪作為載重汽車的主減速器 而是采用弧齒錐齒輪。 關(guān)鍵詞:載重汽車;驅(qū)動(dòng)橋;雙級主減速器;全浮式半軸 哈爾濱工業(yè)大學(xué)華德應(yīng)用技術(shù)學(xué)院畢業(yè)設(shè)計(jì)(論文) II Abstract As a vehicle drive axle assembly of one of the four, and its performance will have a direct impact on vehicle performance, and it is particularly important for trucks. When using high- power engine torque output of large trucks to meet the current fast, heavy-duty high-efficiency, cost-effective and necessary, must be with an efficient, reliable bridge driver. Therefore, efficient use of transmission of a double-stage driver slow down the bridge has become a heavy-duty motor vehicles in the future development direction. In this paper, in the light of the traditional design of the drive axle of the truck driver for the design of the bridge. This article first identified the major components of the structure and main design parameters; then a similar reference to the drive axle of the structure to determine the overall design of the program; on the final owner, Gear Driven cone, cone differential planetary gear, axle gear, the all-floating Half-bridge and the overall strength of the shell to carry out verification as well as support for the life of bearing checking. This article is not a traditional double-bevel gear surface as the main reducer truck instead of using the spiral bevel gear, as a hope that this will continue to study this issue. Keyword truck driver bridge double-stage bridge slowdown spiral bevel gear 哈爾濱工業(yè)大學(xué)華德應(yīng)用技術(shù)學(xué)院畢業(yè)設(shè)計(jì)(論文) III 目 錄 摘要 ...............................................................................................................................I Abstractb...................................................................................................................Ⅱ 第 1章 緒論 .................................................................................................................1 第 2章 驅(qū)動(dòng)橋總成的結(jié)構(gòu)型式 .................................................................................4 2.1 驅(qū)動(dòng)橋總體方案的確定 ...................................................................................4 2.1.1 非斷開式驅(qū)動(dòng)橋的結(jié)構(gòu)分析 .............................................................4 2.1.2 斷開式驅(qū)動(dòng)橋的結(jié)構(gòu)分析 .................................................................5 2.2 本設(shè)計(jì)驅(qū)動(dòng)橋結(jié)構(gòu)形式的確定 .......................................................................6 第 3章 主減速器 .........................................................................................................8 3.1 主減速器的結(jié)構(gòu)形式 .......................................................................................8 3.1.1 主減速器的齒輪類型 .........................................................................8 3.1.2 主減速器主從動(dòng)錐齒輪的支承形式 .................................................8 3.2 主減速器的基本參數(shù)選擇與設(shè)計(jì) ...................................................................9 3.2.1 主減速比的確定 .................................................................................9 3.2.2 主減速器計(jì)算載荷的確定 ...............................................................10 3.2.3 主減速器基本參數(shù)的確定 ...............................................................12 3.2.4 主減速器傳動(dòng)齒輪的幾何尺寸計(jì)算 ...............................................13 3.2.5 主減速器軸承的選擇 ........................................................................14 3.2.6 主減速器齒輪的材料及熱處理 .......................................................19 3.2.7 主減速器傳動(dòng)齒輪的強(qiáng)度校核 .......................................................23 第 4章 差速器 .........................................................................................................23 4.1 對稱式圓錐行星齒輪差速器的設(shè)計(jì) .............................................................23 4.1.1 差速器齒輪基本參數(shù)的確定 ...........................................................23 4.1.2 差速器齒輪的幾何尺寸的確定 .......................................................23 哈爾濱工業(yè)大學(xué)華德應(yīng)用技術(shù)學(xué)院畢業(yè)設(shè)計(jì)(論文) IV 4.2 差速器齒輪的強(qiáng)度校核 .................................................................................24 第 5章 驅(qū)動(dòng)半軸設(shè)計(jì) ...............................................................................................26 5.1 全浮式半軸的桿部直徑的初選 .....................................................................26 5.2 全浮式半軸的強(qiáng)度校核 .................................................................................26 5.3 半軸花鍵的強(qiáng)度校核 .....................................................................................26 第 6章 驅(qū)動(dòng)橋橋殼 ...................................................................................................28 6.1 橋殼的結(jié)構(gòu)形式 .............................................................................................28 6.1.1 整體式橋殼結(jié)構(gòu)形式分析 .................................................................28 6.1.2 鑄造整體式橋殼結(jié)構(gòu)形式分析 .........................................................28 6.1.3 鋼板沖壓焊接整體式橋殼 .................................................................28 6.1.4 鋼管擴(kuò)張成形整體式橋殼 .................................................................29 6.2 橋殼的受力分析與強(qiáng)度校核 ..........................................................................29 6.2.1 橋殼的靜彎曲應(yīng)力計(jì)算 .....................................................................29 6.2.2 在不平路面沖擊載荷作用下橋殼的強(qiáng)度校核 .................................30 6.2.3 汽車以最大牽引力行駛時(shí)的橋殼強(qiáng)度校核 .....................................31 6.2.4 汽車緊急制動(dòng)時(shí)的橋殼強(qiáng)度校核 ...................................................33 結(jié)論 .............................................................................................................................35 致謝 .............................................................................................................................36 參考文獻(xiàn) .....................................................................................................................37 哈爾濱工業(yè)大學(xué)華德應(yīng)用技術(shù)學(xué)院畢業(yè)設(shè)計(jì)(論文) - 0 - 第 1章 緒論 汽車驅(qū)動(dòng)橋位于傳動(dòng)系的末端。其基本功用首先是增扭、降速、改變 轉(zhuǎn)矩的傳遞方向,即增大由傳動(dòng)軸或直接從變速器傳來的轉(zhuǎn)矩,并將轉(zhuǎn)矩 合理的分配給左右驅(qū)動(dòng)車輪;其次,驅(qū)動(dòng)橋還要承受作用于路面或車身之 間的垂直力,縱向力和橫向力,以及制動(dòng)力矩和反作用力矩等。驅(qū)動(dòng)橋一 般由主減速器,差速器,車輪傳動(dòng)裝置和橋殼組成。 對于重型載貨汽車來說,要傳遞的轉(zhuǎn)矩較乘用車和客車以及輕型商用 車都要大得多,以便能夠以較低的成本運(yùn)輸較多的貨物,選擇功率較大的 發(fā)動(dòng)機(jī),這就對傳動(dòng)系統(tǒng)有較高的要求,而驅(qū)動(dòng)橋在傳動(dòng)系統(tǒng)中起著舉足 輕重的作用。隨著目前國際上石油價(jià)格的上漲,汽車的經(jīng)濟(jì)性日益成為人 們關(guān)心的話題,這不僅僅只對乘用車,對于載貨汽車,提高其燃油經(jīng)濟(jì)性 也是各商用車生產(chǎn)商來提高其產(chǎn)品市場競爭力的一個(gè)法寶。因?yàn)橐话闱闆r 下重型載貨汽車所采用的發(fā)動(dòng)機(jī)都是大功率,大轉(zhuǎn)矩的。裝載質(zhì)量在十噸 以上的載貨汽車的發(fā)動(dòng)機(jī),最大功率在 140KW 以上,最大轉(zhuǎn)矩也在 700N·m 以上,百公里油耗是一般都在 34 升左右。為了降低油耗,不僅要 在發(fā)動(dòng)機(jī)的環(huán)節(jié)上節(jié)油,而且也需要從傳動(dòng)系中減少能量的損失。這就必 須在發(fā)動(dòng)機(jī)的動(dòng)力輸出之后,在從發(fā)動(dòng)機(jī)—傳動(dòng)軸—驅(qū)動(dòng)橋這一動(dòng)力輸送 環(huán)節(jié)中尋找減少能量在傳遞的過程中的損失。在這一環(huán)節(jié)中,發(fā)動(dòng)機(jī)是動(dòng) 力的輸出者,也是整個(gè)機(jī)器的心臟,而驅(qū)動(dòng)橋則是將動(dòng)力轉(zhuǎn)化為能量的最 終執(zhí)行者。因此,在發(fā)動(dòng)機(jī)相同的情況下,采用性能優(yōu)良且與發(fā)動(dòng)機(jī)匹配 性比較高的驅(qū)動(dòng)橋便成了有效節(jié)油的措施之一。所以設(shè)計(jì)新型的驅(qū)動(dòng)橋成 為新的課題。設(shè)計(jì)驅(qū)動(dòng)橋時(shí)應(yīng)當(dāng)滿足如下基本要求: (1)選擇適當(dāng)?shù)闹鳒p速比,以保證汽車在給定的條件下具有最佳的 動(dòng)力性和燃油經(jīng)濟(jì)性; (2)外廓尺寸小,保證汽車具有足夠的離地間隙,以滿足通過性的 哈爾濱工業(yè)大學(xué)華德應(yīng)用技術(shù)學(xué)院畢業(yè)設(shè)計(jì)(論文) - 1 - 要求; (3)齒輪及其他傳動(dòng)件工作平穩(wěn),噪聲小; (4)在各種載荷和轉(zhuǎn)速工況下有較高的傳動(dòng)效率; (5)具有足夠的強(qiáng)度和剛度,以承受和傳遞作用于路面和車架或車身 間的各種力和力矩;在此條件下,盡可能降低質(zhì)量,尤其是簧下質(zhì) 量,減少不平路面的沖擊載荷,提高汽車的平順性; (6)與懸架導(dǎo)向機(jī)構(gòu)運(yùn)動(dòng)協(xié)調(diào); (7)結(jié)構(gòu)簡單,加工工藝性好,制造容易,維修,調(diào)整方便。 目前我國正在大力發(fā)展汽車產(chǎn)業(yè),采用后輪驅(qū)動(dòng)汽車的平衡性和操縱 性都將會(huì)有很大的提高。后輪驅(qū)動(dòng)的汽車加速時(shí),牽引力將不會(huì)由前輪發(fā) 出,所以在加速轉(zhuǎn)彎時(shí),司機(jī)就會(huì)感到有更大的橫向握持力,操作性能變 好。維修費(fèi)用低也是后輪驅(qū)動(dòng)的一個(gè)優(yōu)點(diǎn),盡管由于構(gòu)造和車型的不同, 這種費(fèi)用將會(huì)有很大的差別。如果你的變速器出了故障,對于后輪驅(qū)動(dòng)的 汽車就不需要對差速器進(jìn)行維修,但是對于前輪驅(qū)動(dòng)的汽車來說也許就有 這個(gè)必要了,因?yàn)檫@兩個(gè)部件是做在一起的。 所以后輪驅(qū)動(dòng)必然會(huì)使得乘車更加安全、舒適,從而帶來可觀的經(jīng)濟(jì) 效益。通過對驅(qū)動(dòng)橋的設(shè)計(jì),使所選車型能達(dá)到最佳的動(dòng)力性和經(jīng)濟(jì)性, 并采用標(biāo)準(zhǔn)化設(shè)計(jì),使其修理保養(yǎng)方便,進(jìn)行優(yōu)化設(shè)計(jì),可靠性設(shè)計(jì)等內(nèi) 容,更好地學(xué)習(xí)并掌握現(xiàn)代汽車設(shè)計(jì)與機(jī)械設(shè)計(jì)的全面知識(shí)和技能。 本設(shè)計(jì)驅(qū)動(dòng)橋車型技術(shù)參數(shù)如表 1-1 所示。 表 1-1 技術(shù)參數(shù) 最高車速 87km/h 整車重量 5.02 噸 額定載重 2.8 噸 最大總質(zhì)量 8.015 噸 哈爾濱工業(yè)大學(xué)華德應(yīng)用技術(shù)學(xué)院畢業(yè)設(shè)計(jì)(論文) - 2 - 續(xù)表 1-1 技術(shù)參數(shù) 最大載重 9.95 噸 最大輸出功率 88kw 最大輸出扭矩 835Nm 后橋允許載荷 5.085 噸 變速器檔位數(shù) 6 1 檔傳動(dòng)比 6.515 2 檔傳動(dòng)比 3.796 3 檔傳動(dòng)比 2.284 4 檔傳動(dòng)比 1.248 5 檔傳動(dòng)比 1 6 檔傳動(dòng)比 0.85 哈爾濱工業(yè)大學(xué)華德應(yīng)用技術(shù)學(xué)院畢業(yè)設(shè)計(jì)(論文) - 3 - 第 2章 驅(qū)動(dòng)橋總成的結(jié)構(gòu) 2.1驅(qū)動(dòng)橋總體方案的確定 驅(qū)動(dòng)橋的結(jié)構(gòu)型式按工作特性分,可以歸并為兩大類,即非斷開式驅(qū) 動(dòng)橋和斷開式驅(qū)動(dòng)橋。當(dāng)驅(qū)動(dòng)車輪采用非獨(dú)立懸架時(shí),應(yīng)該選用非斷開式 驅(qū)動(dòng)橋;當(dāng)驅(qū)動(dòng)車輪采用獨(dú)立懸架時(shí),則應(yīng)該選用斷開式驅(qū)動(dòng)橋。因此, 前者又稱為非獨(dú)立懸架驅(qū)動(dòng)橋;后者稱為獨(dú)立懸架驅(qū)動(dòng)橋。獨(dú)立懸架驅(qū)動(dòng) 橋結(jié)構(gòu)叫復(fù)雜,但可以大大提高汽車在不平路面上的行駛平順性。 2.1.1 非斷開式驅(qū)動(dòng)橋的結(jié)構(gòu)分析 非斷開式驅(qū)動(dòng)橋是指主減速器和半軸裝在整體的橋殼內(nèi),該形式車橋 和車輪只能隨路面的變化而變化,使車橋整體上下跳動(dòng)。由于結(jié)構(gòu)簡單、 造價(jià)低廉、工作可靠,廣泛用在各種載貨汽車、客車和公共汽車上,在多 數(shù)的越野汽車和部分轎車上也采用這種結(jié)構(gòu)。他們的具體結(jié)構(gòu)、特別是橋 殼結(jié)構(gòu)雖然各不相同,但是有一個(gè)共同特點(diǎn),即橋殼是一根支承在左右驅(qū) 動(dòng)車輪上的剛性空心梁,齒輪及半軸等傳動(dòng)部件安裝在其中。這時(shí)整個(gè)驅(qū) 動(dòng)橋、驅(qū)動(dòng)車輪及部分傳動(dòng)軸均屬于簧下質(zhì)量,汽車簧下質(zhì)量較大,這是 它的一個(gè)缺點(diǎn)。 驅(qū)動(dòng)橋的輪廓尺寸主要取決于主減速器的型式。在汽車輪胎尺寸和驅(qū) 動(dòng)橋下的最小離地間隙已經(jīng)確定的情況下,也就限定了主減速器從動(dòng)齒輪 直徑的尺寸。在給定速比的條件下,如果單級主減速器不能滿足離地間隙 要求,可該用雙級結(jié)構(gòu)。在雙級主減速器中,通常把兩級減速器齒輪放在 一個(gè)主減速器殼體內(nèi),也可以將第二級減速齒輪作為輪邊減速器。對于輪 邊減速器:越野汽車為了提高離地間隙,可以將一對圓柱齒輪構(gòu)成的輪邊 減速器的主動(dòng)齒輪置于其從動(dòng)齒輪的垂直上方;公共汽車為了降低汽車的 質(zhì)心高度和車廂地板高度,以提高穩(wěn)定性和乘客上下車的方便,可將輪邊 減速器的主動(dòng)齒輪置于其從動(dòng)齒輪的垂直下方;有些雙層公共汽車為了進(jìn) 哈爾濱工業(yè)大學(xué)華德應(yīng)用技術(shù)學(xué)院畢業(yè)設(shè)計(jì)(論文) - 4 - 一步降低車廂地板高度,在采用圓柱齒輪輪邊減速器的同時(shí),將主減速器 及差速器總成也移到一個(gè)驅(qū)動(dòng)車輪的旁邊。 在少數(shù)具有高速發(fā)動(dòng)機(jī)的大型公共汽車、多橋驅(qū)動(dòng)汽車和超重型載貨 汽車上,有時(shí)采用蝸輪式主減速器,它不僅具有在質(zhì)量小、尺寸緊湊的情 況下可以得到大的傳動(dòng)比以及工作平滑無聲的優(yōu)點(diǎn),而且對汽車的總體布 置很方便。 2.1.2 斷開式驅(qū)動(dòng)橋的結(jié)構(gòu)分析 斷開式驅(qū)動(dòng)橋區(qū)別于非斷開式驅(qū)動(dòng)橋的明顯特點(diǎn)在于前者沒有一個(gè)連 接左右驅(qū)動(dòng)車輪的剛性整體外殼或梁。斷開式驅(qū)動(dòng)橋的橋殼是分段的,并 且彼此之間可以做相對運(yùn)動(dòng),所以這種橋稱為斷開式的。另外,它又總是 與獨(dú)立懸掛相匹配,故又稱為獨(dú)立懸掛驅(qū)動(dòng)橋。這種橋的中段,主減速器 及差速器等是懸置在車架橫粱或車廂底板上,或與脊梁式車架相聯(lián)。主減 速器、差速器與傳動(dòng)軸及一部分驅(qū)動(dòng)車輪傳動(dòng)裝置的質(zhì)量均為簧上質(zhì)量。 兩側(cè)的驅(qū)動(dòng)車輪由于采用獨(dú)立懸掛則可以彼此致立地相對于車架或車廂作 上下擺動(dòng),相應(yīng)地就要求驅(qū)動(dòng)車輪的傳動(dòng)裝置及其外殼或套管作相應(yīng)擺動(dòng)。 汽車懸掛總成的類型及其彈性元件與減振裝置的工作特性是決定汽車行駛 平順性的主要因素,而汽車簧下部分質(zhì)量的大小,對其平順性也有顯著的 影響。斷開式驅(qū)動(dòng)橋的簧下質(zhì)量較小,又與獨(dú)立懸掛相配合,致使驅(qū)動(dòng)車 輪與地面的接觸情況及對各種地形的適應(yīng)性比較好,由此可大大地減小汽 車在不平路面上行駛時(shí)的振動(dòng)和車廂傾斜,提高汽車的行駛平順性和平均 行駛速度,減小車輪和車橋上的動(dòng)載荷及零件的損壞,提高其可靠性及使 用壽命。但是,由于斷開式驅(qū)動(dòng)橋及與其相配的獨(dú)立懸掛的結(jié)構(gòu)復(fù)雜,故 這種結(jié)構(gòu)主要見于對行駛平順性要求較高的轎車及一些越野汽車上,且后 者多屬于輕型以下的越野汽車或多橋驅(qū)動(dòng)的重型越野汽車。 哈爾濱工業(yè)大學(xué)華德應(yīng)用技術(shù)學(xué)院畢業(yè)設(shè)計(jì)(論文) - 5 - 由于要求本課題設(shè)計(jì)的是 9.95 噸級的后驅(qū)動(dòng)橋,要設(shè)計(jì)這樣一個(gè)級 別的驅(qū)動(dòng)橋,一般選用非斷開式結(jié)構(gòu)以與非獨(dú)立懸架相適應(yīng),且非斷開式 驅(qū)動(dòng)橋結(jié)構(gòu)簡單、造價(jià)低廉、工作可靠,查閱資料,可參照國內(nèi)相關(guān)貨車 的設(shè)計(jì),最后本課題選用非斷開式驅(qū)動(dòng)橋。該種形式的驅(qū)動(dòng)橋的橋殼是一 根支撐在左右驅(qū)動(dòng)車輪的剛性空心梁,一般是鑄造或鋼板沖壓而成,主減 速器,差速器和半軸等所有傳動(dòng)件都裝在其中,此時(shí)驅(qū)動(dòng)橋,驅(qū)動(dòng)車輪都 屬于簧下質(zhì)量。 重型汽車驅(qū)動(dòng)橋技術(shù)已呈現(xiàn)出向雙級化發(fā)展的趨勢,主要是雙級驅(qū)動(dòng) 橋還有以下幾點(diǎn)優(yōu)點(diǎn): (l) 雙級減速驅(qū)動(dòng)橋是驅(qū)動(dòng)橋中結(jié)構(gòu)最簡單的一種,制造工藝簡單, 成本較低,是驅(qū)動(dòng)橋的基本類型,在重型汽車上占有重要地位; (2) 重型汽車發(fā)動(dòng)機(jī)向低速大轉(zhuǎn)矩發(fā)展的趨勢,使得驅(qū)動(dòng)橋的傳動(dòng)比 向小速比發(fā)展; (3) 隨著公路狀況的改善,特別是高速公路的迅猛發(fā)展,重型汽車使 用條件對汽車通過性的要求降低。因此,重型汽車不必像過去一樣,采用 復(fù)雜的結(jié)構(gòu)提高通過性; (4) 與帶輪邊減速器的驅(qū)動(dòng)橋相比,由于產(chǎn)品結(jié)構(gòu)簡化,雙級減速驅(qū) 動(dòng)橋機(jī)械傳動(dòng)效率提高,易損件減少,可靠性提高。 雙級橋產(chǎn)品的優(yōu)勢為雙級橋的發(fā)展拓展了廣闊的前景。從產(chǎn)品設(shè)計(jì)的 角度看, 重型車產(chǎn)品在主減速比小于 6 的情況下,應(yīng)盡量選用雙級減速 驅(qū)動(dòng)橋。 所以此設(shè)計(jì)采用雙級主減速器再配以整體式橋殼。 2.2本設(shè)計(jì)驅(qū)動(dòng)橋結(jié)構(gòu)形式的確定 普通非斷開式驅(qū)動(dòng)橋,由于其結(jié)構(gòu)簡單,造價(jià)低廉,工作可靠,廣泛 地用在各種載貨汽車及公共汽車上,在多數(shù)的越野汽車上也采用這種結(jié)構(gòu)。 哈爾濱工業(yè)大學(xué)華德應(yīng)用技術(shù)學(xué)院畢業(yè)設(shè)計(jì)(論文) - 6 - 普通的非斷開式驅(qū)動(dòng)橋的特點(diǎn)是一根支撐在左右驅(qū)動(dòng)車輪上的剛性 空心梁,而主減速器、差速器及半軸等傳動(dòng)件都裝在其中。這時(shí),整個(gè)驅(qū) 動(dòng)橋和驅(qū)動(dòng)車輪的質(zhì)量以及傳動(dòng)軸的部分質(zhì)量都屬于汽車的非懸掛質(zhì)量, 使汽車的非懸掛質(zhì)量較大,這是普通非斷開式驅(qū)動(dòng)橋的一個(gè)弱點(diǎn),這種驅(qū) 動(dòng)橋和輪轂,制動(dòng)器及制動(dòng)鼓的總質(zhì)量約占一般汽車底盤質(zhì)量的 11%---16%。 圖 2-1 非斷開式驅(qū)動(dòng)橋 哈爾濱工業(yè)大學(xué)華德應(yīng)用技術(shù)學(xué)院畢業(yè)設(shè)計(jì)(論文) - 7 - 第 3章 主減速器 3.1 主減速器的結(jié)構(gòu)形式 主減速器的結(jié)構(gòu)形式按參加減速傳動(dòng)的齒輪副數(shù)目分,有單級主減速 器和雙級主減速器。 3.1.1 主減速器的齒輪類型 主減速器的齒輪有弧齒錐齒輪,雙曲面齒輪,圓柱齒輪和蝸輪蝸桿等 形式?;↓X錐齒輪傳動(dòng),其特點(diǎn)是可以承受較大的負(fù)荷,加之其輪齒不是 在齒的全長上同時(shí)嚙合,而是逐漸有齒的一端連續(xù)而平穩(wěn)的地轉(zhuǎn)向另一端, 工作平穩(wěn),噪聲和振動(dòng)小,所以在此選用弧齒錐齒輪傳動(dòng)。 3.1.2 主減速器主從動(dòng)錐齒輪的支承形式 作為一個(gè) 9.95 噸級的驅(qū)動(dòng)橋,傳動(dòng)的轉(zhuǎn)矩較大,所以主動(dòng)錐齒輪采用 懸臂式支承,如圖 3-1 所示。 圖 3-1 主動(dòng)錐齒輪跨置式 從動(dòng)錐齒輪采用圓錐滾子軸承支承。為了增加支承剛度,兩軸承的圓 錐滾子大端應(yīng)向內(nèi),以減小尺寸 c+d。為了使從動(dòng)錐齒輪背面的差速器殼 體處有足夠的位置設(shè)置加強(qiáng)肋以增強(qiáng)支承穩(wěn)定性,c+d 應(yīng)不小于從動(dòng)錐齒 輪大端分度圓直徑的 70%。為了使載荷能均勻分配在兩軸承上,應(yīng)使 c 等 于或大于 d,如圖 3-2 所示。 哈爾濱工業(yè)大學(xué)華德應(yīng)用技術(shù)學(xué)院畢業(yè)設(shè)計(jì)(論文) - 8 - 圖 3-2 從動(dòng)錐齒輪支撐形式 3.2 主減速器的基本參數(shù)選擇與設(shè)計(jì) 3.2.1 主減速比的確定 在給定發(fā)動(dòng)機(jī)最大功率 及其轉(zhuǎn)速 的情況下,所選擇的 i 值應(yīng)amxPpn0 能保證這些汽車有盡可能高的最高車速 。這時(shí) i 值應(yīng)按下式來確定:amxv0 (3-1)rp0amxghni=.37vi 式中: ——車輪的滾動(dòng)半徑, =0.5m;r r igh——變速器量高檔傳動(dòng)比。i gh =1。 對于其他汽車來說,為了得到足夠的功率儲(chǔ)備而使最高車速稍有下降, i 一般選擇比上式求得的大 10%~25%,即按下式選擇:0 (3-2)rp0amxghFLBni=(.37~.42)vi 式中: i——分動(dòng)器或加力器的高檔傳動(dòng)比; iLB——輪邊減速器的傳動(dòng)比。 哈爾濱工業(yè)大學(xué)華德應(yīng)用技術(shù)學(xué)院畢業(yè)設(shè)計(jì)(論文) - 9 - 計(jì)算出 i =4.450 3.2.2 主減速器計(jì)算載荷的確定 按發(fā)動(dòng)機(jī)最大轉(zhuǎn)矩和最低擋傳動(dòng)比確定從動(dòng)錐齒輪的計(jì)算轉(zhuǎn)矩Tce (3-nKiTToLec /max????mN? 3) 式中: ——發(fā)動(dòng)機(jī)至所計(jì)算的主減速器從動(dòng)錐齒輪之間的傳動(dòng)系的最低TLi 擋傳動(dòng)比,在此取 6.5; ——發(fā)動(dòng)機(jī)的輸出的最大轉(zhuǎn)矩,在此取 835 ;maxe mN? ——傳動(dòng)系上傳動(dòng)部分的傳動(dòng)效率,在此取 0.9;T? ——該汽車的驅(qū)動(dòng)橋數(shù)目在此取 1;n ——由于猛結(jié)合離合器而產(chǎn)生沖擊載荷時(shí)的超載系數(shù),對于一般oK 的載貨汽車 =1.0,當(dāng)性能系數(shù) >0 時(shí)可取 =2.0。oKpfoK (3-??? ????? ????????? 16Tgm0.95 0. Tgm.195-6eaxeaeax當(dāng)當(dāng)pf 4)式中: ——汽車滿載時(shí)的總質(zhì)量在此取 9950 。amgK 所以 0.195 =23.24>16 835109? =-0.33〈0 即 =1.0pfoK 由以上各參數(shù)可求 Tce 哈爾濱工業(yè)大學(xué)華德應(yīng)用技術(shù)學(xué)院畢業(yè)設(shè)計(jì)(論文) - 10 - = =4896.02Tce19.05.683?mN? 按驅(qū)動(dòng)輪打滑轉(zhuǎn)矩確定從動(dòng)錐齒輪的計(jì)算轉(zhuǎn)矩 csT (3-LBriGcs????/2? 5) 式中: ——汽車滿載時(shí)一個(gè)驅(qū)動(dòng)橋給水平地面的最大負(fù)荷,預(yù)2 設(shè)后橋所承載 5085N 的負(fù)荷; ——輪胎對地面的附著系數(shù),對于安裝一般輪胎的公路用? 車,取 =0.85; ——車輪的滾動(dòng)半徑,滾動(dòng)半徑為 0.5m;r , ——分別為所計(jì)算的主減速器從動(dòng)錐齒輪到驅(qū)動(dòng)車LB?i 輪之間的傳動(dòng)效率和傳動(dòng)比, 取 0.9,由于沒有輪LB? 邊減速器 取 1.0。LBi 所以 = =2410.25rcsGT????/2 0.19585?mN? 按汽車日常行駛平均轉(zhuǎn)矩確定從動(dòng)錐齒輪的計(jì)算轉(zhuǎn)矩 cfT (3-?? )( ?????PHRLBrTacf ffni 6) 式中: ——汽車滿載時(shí)的總重量,在此取 9950N;aG ——所牽引的掛車滿載時(shí)總重量,N,但僅用于牽引車的計(jì)算;T ——道路滾動(dòng)阻力系數(shù),計(jì)算時(shí)轎車取 0.010~0.015;對于載貨Rf 哈爾濱工業(yè)大學(xué)華德應(yīng)用技術(shù)學(xué)院畢業(yè)設(shè)計(jì)(論文) - 11 - 汽車可取 0.015~0.020;越野車取 0.020~0.035;在此取 0.018; ——汽車正常行駛時(shí)的平均爬坡能力系數(shù),對于載貨汽車可取Hf 0.05~0.09 在此取 0.07; ——汽車的性能系數(shù)在此取 0。pf 所以 ?? )(PHRLBrTacf ffniG?????? m486.N07.18.0.95???cf 3.2.3 主減速器基本參數(shù)的確定 主減速器齒輪的主要參數(shù)有一級傳動(dòng)主、從動(dòng)齒輪的齒數(shù) 和 ,從1z2 動(dòng)錐齒輪大端分度圓直徑 、端面模數(shù) 、主從動(dòng)錐齒輪齒面寬 和 ,2Dtm1b2 二級傳動(dòng)主、從動(dòng)齒輪齒數(shù) 和 、模數(shù)和齒厚等。3z4 一級傳動(dòng)主、從動(dòng)齒輪的齒數(shù)取 =10, =36, + =46〉4012z12z 從動(dòng)錐齒輪大端分度圓直徑 和端面模數(shù)2Dtm 可根據(jù)經(jīng)驗(yàn)公式初選,即2D (3-7)322cDTK? 式中: ——直徑系數(shù),一般取 13.0~16.0;2D ——從動(dòng)錐齒輪的計(jì)算轉(zhuǎn)矩, ,為 Tce 和 Tcs 中的較小者。Tc mN? 所以 =( 13.0~16.0 ) =200.92325.401 哈爾濱工業(yè)大學(xué)華德應(yīng)用技術(shù)學(xué)院畢業(yè)設(shè)計(jì)(論文) - 12 - 初選 =200.9 則 = / =200.9/36=5.582Dtm2Dz 有參考《機(jī)械設(shè)計(jì)手冊》表 23.4-3 中 選取 6 t 對于一級傳動(dòng)從動(dòng)錐齒輪齒面寬 ,推薦不大于節(jié)錐 的 0.3 倍,即2b2A ,而且 應(yīng)滿足 ,對于汽車主減速器圓弧齒輪推薦采223.0Ab?2btm10? 用: =0.155 200.9=31.1 在此取 3115D?? 通常小齒輪的齒面加大 10%較為合適,在此取 =341b 二級傳動(dòng)主、從動(dòng)齒輪的齒數(shù)取 =15, =55,從動(dòng)齒輪 的模數(shù)取 m=43z44z 二級傳動(dòng)從動(dòng)齒輪齒厚 =73, =66。3b4 3.2.4 主減速器傳動(dòng)齒輪的幾何尺寸計(jì)算 主減速器一級傳動(dòng)齒輪的幾何尺寸如表 3-1 所示。 表 3-1 主減速器一級傳動(dòng)齒輪的幾何尺寸 序 號 項(xiàng) 目 計(jì) 算 公 式 計(jì) 算 結(jié) 果 1 主動(dòng)齒輪齒數(shù) 1z10 2 從動(dòng)齒輪齒數(shù) 2 36 3 端面模數(shù) m6㎜ 4 齒面寬 b =34㎜ 1b =31㎜2 5 全齒高 h =13.2㎜h 6 法向壓力角 ?=22.5°? 7 軸交角 ?=90°? 8 節(jié)圓直徑 =dmz 60㎜?1d =216㎜2 哈爾濱工業(yè)大學(xué)華德應(yīng)用技術(shù)學(xué)院畢業(yè)設(shè)計(jì)(論文) - 13 - 9 節(jié)錐角 arctan?1?21z=15.52°1? 10 節(jié)錐距 A = 1sin d0A =111.11㎜0 11 周節(jié) t=3.1416 mt=18.85㎜ 12 齒頂高 ah=6㎜ah 13 齒根高 f =7.2 ㎜f 14 徑向間隙 c= mc*c=2.31㎜ 15 齒根角 0artnAhff??f?=2.91 ° 16 面錐角 21f??2fa=15.61°1a? =80.27°2 續(xù)表 3-1 主減速器一級傳動(dòng)齒輪幾何尺寸 17 根錐角 =1f?1f?? =2f2f =9.79°1f? =74.51°2f 18 齒頂圓直徑 11cos?aahd?? =2a21cos?hd? =71.52㎜ad =222.36㎜2 主減速器二級傳動(dòng)齒輪的幾何尺寸如表 3-2 所示。 表 3-2 主減速器二級傳動(dòng)齒輪的幾何尺寸 序 號 項(xiàng) 目 計(jì) 算 公 式 計(jì) 算 結(jié) 果 1 主動(dòng)齒輪齒數(shù) 3z15 哈爾濱工業(yè)大學(xué)華德應(yīng)用技術(shù)學(xué)院畢業(yè)設(shè)計(jì)(論文) - 14 - 2 從動(dòng)齒輪齒數(shù) 4z55 3 端面模數(shù) m4㎜ 4 齒厚 b =73㎜ 3b =66㎜4 5 中心距 a a=140㎜ 6 節(jié)圓直徑 =dmz 60㎜?3d =220㎜4 7 齒頂高 ah=4㎜ah 8 齒根高 f =5㎜f 9 齒頂圓直徑 3ad4 =68㎜3ad =228㎜4 3.2.5 主減速器軸承的選擇 作用在主動(dòng)錐齒輪齒面上的軸向力 A 和徑向力 R 分別為 (3-8)????????cosinstacossin????FFSNaz (3-9)itnsico??SRz 可計(jì)算 14946.6N? ???????? 52.1cos3i52.1i.ta35cs107.8azF =5435.12NRz ?? .in.cos.tno. 對于采用跨置式的主動(dòng)錐齒輪和從動(dòng)錐齒輪的軸承徑向載荷,如圖 3-5 所示。 哈爾濱工業(yè)大學(xué)華德應(yīng)用技術(shù)學(xué)院畢業(yè)設(shè)計(jì)(論文) - 15 - 圖 3-5 主減速器軸承的布置尺寸 軸承 A,B 的徑向載荷分別為 R = (3-???225.01maZRZdFbFa????? 10) (3-22.maZRZBc???? 11) 根據(jù)上式已知 =14947N, =5435N,a=91mm ,b=63mm,c=28mmaZFRZ 所以軸承 A 的徑向 =A????22 7.5149.063546318709 ???? =12956N 其軸向力為 0 軸承 B 的徑向力 R =B????22 7.5149.06354815709 ??? =8223N (1)對于軸承 A,采用圓錐滾子軸承 30208,此軸承的額定動(dòng)載荷 Cr 哈爾濱工業(yè)大學(xué)華德應(yīng)用技術(shù)學(xué)院畢業(yè)設(shè)計(jì)(論文) - 16 - 為 105.65KN,所承受的當(dāng)量動(dòng)載荷 Q=X·R =1×12956=12956N。所以有A 公式 s (3-12)610???????? ?QfCrLpt 式中: ——為溫度系數(shù),在此取 1.0;tf ——為載荷系數(shù),在此取 1.2。p 所以 = =5.94×10 sL63 10295.16????????8 此外對于無輪邊減速器的驅(qū)動(dòng)橋來說,主減速器的從動(dòng)錐齒輪軸承的計(jì)算 轉(zhuǎn)速 為2n r/min (3-13)ramv6.? 式中: ——輪胎的滾動(dòng)半徑;r ——汽車的平均行駛速度,km/h;對于載貨汽車和公共汽車可取amv 30~35 km/h,在此取 33 km/h。 所以有上式可得 = =175.56 r/min2n5.036? 而主動(dòng)錐齒輪的計(jì)算轉(zhuǎn)速 =175.56×5.4=948.024r/min1 所以軸承能工作的額定軸承壽命: h (3-14) nLh60? 式中: ——軸承的計(jì)算轉(zhuǎn)速,r/min。 有上式可得軸承 A 的使用壽命 =10442.8 h024.98615??hL 哈爾濱工業(yè)大學(xué)華德應(yīng)用技術(shù)學(xué)院畢業(yè)設(shè)計(jì)(論文) - 17 - 若大修里程 S 定為 100000 公里,可計(jì)算出預(yù)期壽命即 = h (3-15)hL'amv 所以 = =3030.30 h'310 和 比較, 〉 ,故軸承符合使用要求。hh' (2)對于軸承 B,在此選用 30207 型軸承。 在此徑向力 R=8223N 軸向力 A=17625N,所以 =2.14>e 由《機(jī)械設(shè)RA 計(jì)》可查得 X=0.4,Y=0.4cota=0.4×cot =0.97。?5.2 當(dāng)量動(dòng)載荷 Q= (3-16)??YAXRfd? 式中: ——沖擊載荷系數(shù)在此取 1.2。df 有上式可得 Q=1.2(0.4×8223+0.97×17625)=24462.5N 所以軸承的使用壽命由式(3-19)和式(3-20)可得 = = =10833.7 h>3030.30h=hL ???????QCrn16703105.24689170?????? hL' 所以軸承符合使用要求。 對于軸承 C 采用 30304,軸向力 A=10420N,徑向力 R=8004.6;所以 =1.3>e 由《機(jī)械設(shè)計(jì)》可查得RA X=0.4,Y=0.4cota =0.4×cot =0.97。?5.2 Q= =1.2( 0.4×10420+0.97×8004.6)=14318.9N ??YRXfd? = = =16561h>hL ???????QCrn16703109.48756.10??????hL' 軸承 C 符合要求。 軸承 D 采用 30208,軸向力 A=12560N,徑向力 R=19445.8N, =0.65>eRA 得 X=0.4,Y=0.4cota =0.4×cot =0.97。?5.2 哈爾濱工業(yè)大學(xué)華德應(yīng)用技術(shù)學(xué)院畢業(yè)設(shè)計(jì)(論文) - 18 - Q= =1.2(0.4×12560+0.97×19445.8 ) =28663.7N ??YRXAfd? = = =16759.3h>hL ???????QCrn16703107.286495.10??????hL' 軸承 D 滿足使用要求。 軸承 E,F 的徑向力計(jì)算公式為: =ER????22 1.864975.065436185702 ??? =12352.6N =F 22 ..18 =16387.6N 軸承 E,F 采用 30208 圓錐滾子軸承。 對于軸承 E,軸向力 A=12560N,徑向力 R=16387.6N =1.02>e 得 X=0.4,Y=0.4cota=0.4×cot =0.97RA ?5.2 Q= =1.2(0.4×12560+0.97×12352.6 ) =20407.2N ??YXfd? = = =21863.5h>hL ???????QCrn16703102.47956.10??????hL' 軸承 E 符合使用要求。 對于軸承 F,軸向力 A=12560N,徑向力 R=16387.6N =0.77>e 得 X=0.4,Y=0.4cota=0.4×cot =0.97。RA ?5.2 Q= =1.2(0.4×12560+0.97×16387.6 ) =25103.9N ??YXfd? = = =24032.7h>hL ???????QCrn16703109.25476.10??????hL' 軸承 F 符合使用要求。 3.2.6 主減速器齒輪的材料及熱處理 在此,齒輪所采用的鋼為 20CrMnTi 哈爾濱工業(yè)大學(xué)華德應(yīng)用技術(shù)學(xué)院畢業(yè)設(shè)計(jì)(論文) - 19 - 用滲碳合金鋼制造的齒輪,經(jīng)過滲碳、淬火、回火。 3.2.7 主減速器圓弧錐齒輪的強(qiáng)度校核 (1) 單位齒長上的圓周力 N/ mm (3-17)2bPp? 式中: P——作用在齒輪上的圓周力,按發(fā)動(dòng)機(jī)最大轉(zhuǎn)矩 Temax 和最大附著 力矩 兩種載荷工況進(jìn)行計(jì)算,N; rG?2 ——從動(dòng)齒輪的齒面寬,在此取 31mm。 2b 按發(fā)動(dòng)機(jī)最大轉(zhuǎn)矩計(jì)算時(shí): N/mm (3-21 3max0bdiTpge?? 18) 式中: ——發(fā)動(dòng)機(jī)輸出的最大轉(zhuǎn)矩,在此取 835 ;maxeT mN? ——變速器的傳動(dòng)比;gi ——主動(dòng)齒輪節(jié)圓直徑,在此取 60mm。1d 按上式 N/mm2.763126085.3???p 按最大附著力矩計(jì)算時(shí): N/mm (3-19)2 30bdrGp?? 式中: 哈爾濱工業(yè)大學(xué)華德應(yīng)用技術(shù)學(xué)院畢業(yè)設(shè)計(jì)(論文) - 20 - ——汽車滿載時(shí)一個(gè)驅(qū)動(dòng)橋給水平地面的最大負(fù)荷,在此取2G 5085N; 按上式= 742.61 N/mm???312605.850 3p 其中上述兩種方法計(jì)算用的許用單位齒長上的圓周力[p]都為 1865N/mm 。2 (2)輪齒的彎曲強(qiáng)度校核 汽車主減速器錐齒輪的齒根彎曲應(yīng)力為 N/ (3-JmzbKTvs????20 31?2 20) 式中: ——該齒輪的計(jì)算轉(zhuǎn)矩,Nm;T ——超載系數(shù);在此取 1.0;0K ——尺寸系數(shù),反映材料的不均勻性,與齒輪尺寸和熱處理有關(guān),s 當(dāng)m 時(shí), ,在此 =0.7;6.1?4.25mKs?4.256?sK ——載荷分配系數(shù), =1.00~1.10;m ——質(zhì)量系數(shù),對于汽車驅(qū)動(dòng)橋齒輪,可取 1.0;v ——計(jì)算齒輪的齒面寬;b ——計(jì)算彎曲應(yīng)力的綜合系數(shù),按圖 3--3 選取小齒輪的J =0.225,大齒輪 =0.195 。J 哈爾濱工業(yè)大學(xué)華德應(yīng)用技術(shù)學(xué)院畢業(yè)設(shè)計(jì)(論文) - 21 - 按上式 =95.75 N/ < 210.9 N/2 31 65.041782???? 2m2m =128.83 N/ <210.9 N/ .2 32 22 所以主減速器齒輪滿足彎曲強(qiáng)度要求。 圖 3-3 彎曲計(jì)算用綜合系數(shù) J (3) 輪齒的表面接觸強(qiáng)度校核 錐齒輪的齒面接觸應(yīng)力為: N/ (3-21)bJKTdCvfmspj 30112???2 式中: ——主動(dòng)齒輪的計(jì)算轉(zhuǎn)矩; ——材料的彈性系數(shù),對于鋼制齒輪副取 232.6 /mm;pC 2 1N ——尺寸系數(shù),在缺乏經(jīng)驗(yàn)的情況下,可取 1.0;sK ——表面質(zhì)量系數(shù),對于制造精確的齒輪可取 1.0;f ——計(jì)算接觸應(yīng)力的綜合系數(shù)。按圖選取 =0.122。J J 哈爾濱工業(yè)大學(xué)華德應(yīng)用技術(shù)學(xué)院畢業(yè)設(shè)計(jì)(論文) - 22 - 按上式 =802.08 〈1750 N/3412.00548620.3 3???j? 2m 主、從動(dòng)齒輪的齒面接觸應(yīng)力相等。所以均滿足要求。 哈爾濱工業(yè)大學(xué)華德應(yīng)用技術(shù)學(xué)院畢業(yè)設(shè)計(jì)(論文) - 23 - 第 4章 差速器 4.1 對稱式圓錐行星齒輪差速器的設(shè)計(jì) 4.1.1 差速器齒輪基本參數(shù)的確定 行星齒輪選 10 齒,半軸齒輪選 18 齒。 行星齒輪與半軸齒輪的節(jié)錐角 ,1?2 = =29.05° =90°- =60.95°211arctnz??80rta12? 再求出圓錐齒輪的大端端面模數(shù) m m= = = =3.3310sin?zA20si?z??05.9sin18 由于強(qiáng)度的要求在此取 m=5 得 =50 =5×18=9051??md2zd? 行星齒輪安裝孔的直徑 及其深度 L? 行星齒輪的安裝孔的直徑 與行星齒輪軸的名義尺寸相同,而行星齒 輪的安裝孔的深度就是行星齒輪在其軸上的支承長度,通常取: (4-1) ?1.?L (4-2)??nlTc?? 302. (4-3)lc?1. 30? ≈24mm ≈27mm36475.289?241.??L 4.1.2 差速器齒輪的幾何尺寸的確定 差速器齒輪的幾何尺寸如表 4-1 所示。 哈爾濱工業(yè)大學(xué)華德應(yīng)用技術(shù)學(xué)院畢業(yè)設(shè)計(jì)(論文) - 24 - 表 4-1 差速器齒輪的幾何尺寸 序號 項(xiàng)目 計(jì)算公式 計(jì)算結(jié)果 1 行星齒輪齒數(shù) ≥10,應(yīng)盡量取最小值1z =101z 2 半軸齒輪齒數(shù) =14~252 =182 3 模數(shù) m=5mmm 4 齒面寬 b 9mm 5 全齒高 h 11mm 6 壓力角 ?22.5° 7 軸交角 =90°? 8 節(jié)圓直徑 ; 1mzd?2z 501?d92 9 節(jié)錐角 ,21arctnz?190???? =29.05°,?.62 10 節(jié)錐距 210sini? dA?=103.07mm0A 11 周節(jié) =3.1416tm=15.7mmt 12 齒頂高 ah5mm 13 齒根高 f =6mmfh 14 徑向間隙 = - =0.188 +0.051chgm=1.931mmc 4.2 差速器齒輪的強(qiáng)度校核 輪齒彎曲強(qiáng)度 為w? = MPa (4-4) w?JmbzKTvs20 31? 哈爾濱工業(yè)大學(xué)華德應(yīng)用技術(shù)學(xué)院畢業(yè)設(shè)計(jì)(論文) - 25 - 式中: ——差速器一個(gè)行星齒輪傳給一個(gè)半軸齒輪的轉(zhuǎn)矩,其計(jì)算式T 在此 為 734.4N·m;n6.0??T ——差速器的行星齒輪數(shù); ——半軸齒輪齒數(shù);2z ——計(jì)算汽車差速器齒輪彎曲應(yīng)力用的綜合系數(shù)查得 =0.226。J J 圖 4-3 彎曲計(jì)算用綜合系數(shù) 根據(jù)上式 = =926 MPa〈980 MPaw?26.05189.1794.7302?? 所以,差速器齒輪滿足彎曲強(qiáng)度要求。 哈爾濱工業(yè)大學(xué)華德應(yīng)用技術(shù)學(xué)院畢業(yè)設(shè)計(jì)(論文) - 26 - 第 5章 驅(qū)動(dòng)半軸設(shè)計(jì) 驅(qū)動(dòng)車輪的傳動(dòng)裝置位于汽車傳動(dòng)系的末端,其功用是將轉(zhuǎn)矩由差速 器的半軸齒輪傳給驅(qū)動(dòng)車輪。在一般的非斷開式驅(qū)動(dòng)橋上,驅(qū)動(dòng)車輪的傳 動(dòng)裝置就是半軸,半軸將差速器的半軸齒輪與車輪的輪轂聯(lián)接起來,半軸 的形式主要取決半軸的支承形式:普通非斷開式驅(qū)動(dòng)橋的半軸,根據(jù)其外 端支承的形式或受力狀況不同可分為半浮式,3/4 浮式和全浮式,在此由 于是載重汽車,采用全浮式結(jié)構(gòu)。 5.1 全浮式半軸的桿部直徑的初選 全浮式半軸桿部直徑的初選可按下式進(jìn)行 (5-??33 3)18.2~05.(196.0TTd??? 1) 根據(jù)上式 =(29.4~31.2)mm??36.7..2 根據(jù)強(qiáng)度要求在此 取 30mm。d 5.2 全浮式半軸的強(qiáng)度校核 首先是驗(yàn)算其扭轉(zhuǎn)應(yīng)力 :? MPa (5-316dT??? 2) 式中: ——半軸的計(jì)算轉(zhuǎn)矩,Nm 在此取 2937.6Nm;T 哈爾濱工業(yè)大學(xué)華德應(yīng)用技術(shù)學(xué)院畢業(yè)設(shè)計(jì)(論文) - 27 - ——半軸桿部的直徑,mm。d 根據(jù)上式 = = 472 MPa< =(490~588) MPa?30164.297???? 所以滿足強(qiáng)度要求。 5.3 半軸花鍵的強(qiáng)度校核 計(jì)算半軸在承受最大轉(zhuǎn)矩時(shí)還應(yīng)該校核其花鍵的剪切應(yīng)力和擠壓應(yīng) 力。 半軸花鍵的剪切應(yīng)力 為s? MPa (5-3)??bzLdDTpABs?????????410 3 半軸花鍵的擠壓應(yīng)力 為c? MPa (5-??pABABc zLdDT????????????????2410 3 4) 式中: ——半軸承受的最大轉(zhuǎn)矩,Nm ,在此取 2937.6Nm;T ——半軸花鍵的外徑,mm,在此取 30mm;BD ——相配花鍵孔內(nèi)徑,mm,在此取 25mm;Ad ——花鍵齒數(shù);在此取 24;z ——花鍵工作長度,mm,在此取 55mm;pL ——花鍵齒寬,mm,在此取 4mm;b 哈爾濱工業(yè)大學(xué)華德應(yīng)用技術(shù)學(xué)院畢業(yè)設(shè)計(jì)(論文) - 28 - ——載荷分布的不均勻系數(shù),計(jì)算時(shí)取 0.75。? 根據(jù)上式可計(jì)算得 = =53.95 MPas?75.042453016.97 3???????? = =86.32 MPa c?.2. 3??????? 根據(jù)要求當(dāng)傳遞的轉(zhuǎn)矩最大時(shí),以上計(jì)算均滿足要求。 第 6章 驅(qū)動(dòng)橋橋殼 驅(qū)動(dòng)橋橋殼是汽車上的主要零件之一,作用在驅(qū)動(dòng)車輪上的牽引力, 制動(dòng)力,側(cè)向力和垂向力也是經(jīng)過橋殼傳到懸架及車架上。因此,橋殼既 是承載件又是傳動(dòng)件。設(shè)計(jì)時(shí)必須考慮在動(dòng)載下橋殼有足夠的強(qiáng)度和剛度。 6.1 橋殼的結(jié)構(gòu)型式 橋殼的結(jié)構(gòu)型式有三種,即可分式橋殼,整體式橋殼和組合式橋殼。 本設(shè)計(jì)采用整體式橋殼。 6.1.1 整體式橋殼結(jié)構(gòu)形式分析 整體式橋殼的特點(diǎn)是將整個(gè)橋殼制成一個(gè)整體,橋殼猶如一個(gè)整體的 空心梁,其強(qiáng)度和剛度都比較好。 6.1.2 鑄