课程设计说明书(2)

Abstract

Car overall design is based on the total vehicle design objectives, a clear relationship between the various primary and secondary requirements, harmonization, the formation of the vehicle design process. It is extremely important in automotive design design aspects, not only throughout the design process, but also for the assembly, component design and build framework. The level of overall design quality of the car's design quality, performance, advanced, and vitality products play a decisive role.

This paper gives the parameters of the car, the car's overall design. Paper mainly on the transmission, drive axle, steering system and brakes were designed to optimize the parameters of the car, improving the car's performance, making the car to get high efficiency applications. Heavy-duty truck market analysis in the truck's total market demand and macro-economic developments, closely linked. Sustained and stable development of the total economy, market demand for truck driving steadily. Meanwhile, the heavy truck market by the proportion of their needs and policy aspects of the impact. In heavy-duty truck market characteristics: 1 steady growth in market demand, incremental space influenced by the product replacement; 2 gradually strengthen market segmentation, product differentiation by manufacturers, scraping the incremental market; three main consumer of diversification competition in the market freedom, the dispersion increased; 4 by the product market competition shifts to all-round competition. Key words: Overall design; transmission; drive axle; Steering System; brake

目录

1汽车总体设计 ..................................................................................................................................9

1.1确定汽车主要参数..................................................................................................................9 1.2货车驾驶员操作位置尺寸 ..................................................................................................... 10 2 变速器设计 ................................................................................................................................... 11

2.1 变速器主要参数的选择与计算 ............................................................................................. 11

2.1.1挡数的选择 ................................................................................................................ 11 2.1.2传动比的确定 ............................................................................................................. 11 2.1.3中心距A的确定......................................................................................................... 11 2.1.4各档齿轮的分配 ......................................................................................................... 12 2.2齿轮与轴的设计计算 ............................................................................................................ 17

2.2.1齿轮设计与计算 ......................................................................................................... 17 2.2.2轴的设计与计算 ......................................................................................................... 20 2.2.3轴的强度计算 ............................................................................................................. 21

2.2.4 轴承的选择与校核 ..................................................................................................... 24 2.3变速器同步器的选择 ............................................................................................................ 25 2.3.1同步器 ....................................................................................................................... 25 3.1主减速器的齿轮类型 ............................................................................................................ 28 3.2主减速器主，从动锥齿轮的支承形式.................................................................................... 28 3.3主减速器计算载荷的确定 ..................................................................................................... 28 3.4主减速器基本参数的选择 ..................................................................................................... 30 3.4.1主、从动锥齿轮齿数和 ............................................................................................... 30 3.5差速器设计 .......................................................................................................................... 31

3.5.1差速器齿轮的基本参数的选择 .................................................................................... 31 3.5.2行星齿轮球面半径的确定 ........................................................................................... 31 3.5.3行星齿轮与半轴齿轮的选择 ........................................................................................ 32 3.5.4差速器圆锥齿轮模数及半轴齿轮节圆直径的初步确定 ................................................. 32 3.6差速器齿轮的强度计算......................................................................................................... 32 3.7驱动半轴的设计 ................................................................................................................... 32

3.7.1全浮式半轴计算载荷的确定 ........................................................................................ 32

3.7.2全浮式半轴的杆部直径的初选 .................................................................................... 33 3.7.3全浮式半轴的强度计算 ............................................................................................... 33 3.7.4半轴花键的强度计算 .................................................................................................. 34

4 货车转向系的设计 ........................................................................................................................ 35

4.1条件:.................................................................................................................................... 35

4.2选择方案.............................................................................................................................. 35 5 鼓式制动器 ................................................................................................................................. 37

5.1 制动距离S ........................................................................................................................ 37 5.2 制动力分配系数β ............................................................................................................. 38

5.3 前后轴制动器总制动力 ...................................................................................................... 38

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5.4 驻车所需制动力 ................................................................................................................ 39 5.5 驻车所需制动力 ................................................................................................................ 39 5.6 驻车所需制动力 ................................................................................................................ 40

5.6.1 制动鼓内径D .......................................................................................................... 40 5.6.2 摩擦衬片宽度b和包角β ......................................................................................... 40 5.6.3 摩擦衬片起始角β0.................................................................................................. 41 5.6.4 制动器中心到张开力F0作用线的距离e ................................................................... 41 5.6.5 制动蹄支承点位置坐标a和c ................................................................................... 41 5.6.6 摩擦片摩擦系数 ..................................................................................................... 41 5.7 制动器主要零部件的结构设计 ........................................................................................... 41

5.7.1 制动鼓 ..................................................................................................................... 41 5.7.2 制动蹄 ..................................................................................................................... 42 5.7.3 制动底板 ................................................................................................................. 42 5.7.4 制动蹄的支承 .......................................................................................................... 42

5.7.5 制动轮缸 ................................................................................................................. 42

6、参考文献..................................................................................................................................... 43

1汽车总体设计

轴数为二轴，驱动形式为4?2布置形式发动机前置，平头货车

1.1确定汽车主要参数

外廓尺寸货车总长为7400mm，汽车宽度为1800mm，汽车高度为2000 轴距L为4000mm，轮距B为1750mm 前悬Lf为1000，后悬LR为2400 货车车长度取1500mm 车厢尺寸取5700mm

轴荷分配前轴取35% 后轴取65% 百公里燃油消耗量取3L（100t.Km） 最小转弯直径Dmin=15m

通过性几何参数hmin=200、 r1=50、ρ1=4.0

动性参数行车制动初速度为30/（Km*h）制动距离满载为10m 空载为9m试车道宽3m踏板力满载700N空载为450N应急制动制动初速度为30Km*h制动距离20m操纵力手为600N、脚700N

发动机功率75PS/3800—4000r/min 最大扭矩为17.5Kgf.m/2000—2500r/min 离合器为干式盘形摩擦离合器选单片，圆周布置、圆柱螺旋弹簧，推式 主要参数 后备系数?=1.5 单位压力Po=0.25Mpa 摩擦片外径D=66.9mm

内径d=35.45mm 厚度取3.2mm 摩擦因数f=0.25、摩擦面数2 离合器间隙△t=3mm

传动系最小传动比为1.0 最大传动比为6.9

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1.2货车驾驶员操作位置尺寸

R点至车顶棚高950mm R点至地板距离为1370mm

R点至驾驶员踵点的水平距离为700mm 背角α为20o 臀角β为100o 足角γ为90o 坐垫深度440mm

座椅前后最小调整范围140mm 座椅上下最小调整范围70mm 10、靠背高度520mm

11、R点至离合器和制动踏板中心在座椅纵向中心面上的距离为800mm 13、离合器制动踏板的行程200mm

14、转向盘下缘至坐垫上表面的距离160mm 15、转向盘后缘至靠背的距离350mm

16、转向盘下缘至离合器和制动踏板中心在转向柱纵向中心面上的距离为600 17、R点至前圆的水平距离为950mm] 18、R点至仪表盘的水平距离为500mm 19、双人座驾驶室内部宽度为1250mm

20、座椅中心面至前门后支柱内侧的距离为360mm 21、座椅宽度450mm

22、转向盘外缘至侧面障碍物的距离为100mm 23、车门打开时下部通道宽度为250mm

24、离合器踏板中心线至制动踏板纵向中心面的距离110mm

25、离合器踏板纵向中心至通过加速踏板中心的纵向中心面的距离100mm 26、加速踏板纵向中心面至最近障碍物的距离60mm 27、离合器踏板中心面至转向柱纵向中心面的距离100mm 28、转向盘中心对座椅总心的偏移量40mm

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