摘 要

本文主要针对四驱越野车的行驶性能对其车架和制动系统进行设计。车架采用边梁式梯形车架，纵梁采用冷冲压成型的槽钢相互嵌入焊接而成，横梁采用冷冲压成型的槽钢与钢板焊接而成，纵梁与横梁的连接亦采用焊接技术。另外主要对纵梁进行结构设计和强度、刚度的计算校核，对横梁进行结构设计和危险截面的应力计算。制动系统采用液压传动对角线双回路制动系统，其中前轮制动器采用通风盘式制动器，后轮制动器采用实心盘式制动器，制动主缸采用串联式双腔制动主缸。制动系统设计中首先进行整车力学模拟分析，进而对制动器进行力学分析进行结构设计和强度校核，另外对制动轮缸、制动主缸的直径容积进行计算和强度校核。种种设计计算是为了保证该设计具有生产加工和应用的可行性。

关 键 词：四驱越野车 车架 制动系统

Abstract：The paper main for driving performance of four-wheel-drive sport utility

vehicle to design frame and braking system.The frame apply the ladder frame of edge beam, the longeron is welded together in the channel steel of embedded in each other which by the way of cold stamping molding. The beams is welded together in the channel steel and plate which by the way of cold stamping molding too.The connect way of longerons and beems is by the way of welding technology. Another the calculate of strength and stiffness is main for the design of longeron. The calculate to the beems part is the stress of section dangerous.The braking system is hydraulic braking system of diagonal double-loop. In which the front-wheel use the ventilated disc brake brake and the back-wheel use the solid rear disc brakes brakes. The brake master cylinder use the series

type of dual-chamber brake master cylinder-type. First of all,the simulation analysis of vehicle mechanics is used for the design of the braking system. Further, the analysis of brake mechanics in order to structural design and strength check. Another, calculate the diameter of the volume and intensity calibration of the brake wheel cylinder, brake master cylinder. A variety of design and calculation is to ensure the feasbility of processing and application.

Keywords：

Four-wheel-drive sport utility vehicle; Frame; Braking System

前 言 ............................................................................................................................... 5 1 越野车车架设计 ............................................................................................................... 6

1.1 车架概述 ............................................................................................................... 6 1.2 车架的基本要求 ................................................................................................... 6 1.3 越野车车架的结构型式选择 ............................................................................... 6 1.4 车架纵梁、横梁及其联接 ................................................................................... 9 1.5 车架的制造工艺及材料选择 ............................................................................. 10 1.6 车架的设计计算 ................................................................................................. 10

1.6.1 车架尺寸的计算 ....................................................................................... 10 1.6.2 车架纵梁刚度、强度的设计计算 ........................................................... 12 1.6.3 车架横梁的设计计算 ............................................................................... 15

2 制动系统设计方法方案分析 ......................................................................................... 20

2.1 制动系统概述 ..................................................................................................... 20

2.1.1 制动系统的功用 ....................................................................................... 20 2.1.2 制动系统的类型 ....................................................................................... 20 2.1.3 制动系统组成 ........................................................................................... 21 2.1.4 制动系统的基本要求: .............................................................................. 21 2.1.5 制动系统设计的内容 ............................................................................... 23 2.2 制动器的结构型式及选择 ................................................................................. 25

2.2.1 制动器分类 ............................................................................................... 25 2.2.2 制动器设计型式的选择 ........................................................................... 25

3 汽车制动系统力学模型分析 ......................................................................................... 27

3.1 制动时车轮的受力 ............................................................................................. 27

3.1.1 地面制动力 ................................................................................................. 27 3.1.2 制动器制动力 ........................................................................................... 27 3.1.3 地面制动力、制动器制动力与附着力之间的关系 ............................... 28 3.2 地面对前、后车轮的法向反作用力 ................................................................. 29 3.3 理想的前、后制动器制动力分配曲线 ............................................................. 30 4 制动器的设计计算 ......................................................................................................... 31

4.1 越野车制动器的力学计算 ................................................................................. 31 4.2 同步附着系数 ..................................................................................................... 32 4.3 制动力分配系数 ................................................................................................. 33 4.4 制动强度和附着系数利用率 ............................................................................. 33 4.5 制动器最大制动力矩 ......................................................................................... 34 4.6 制动器因数 ......................................................................................................... 34 4.7 制动器摩擦系数 ................................................................................................. 34 4.8 摩擦衬块的磨损特性计算 ................................................................................. 34 4.9 制动器的热容量和温升的核算 ......................................................................... 35 4.10 制动器制动力矩的计算 ................................................................................... 36 4.11 驻车制动计算 ................................................................................................... 38 5 液压制动驱动机构的设计计算 ................................................................................... 39

5.1 制动轮缸的设计计算 ......................................................................................... 39

5.1.1 制动轮缸直径与工作容积的计算 ........................................................... 39 5.1.2 制动轮缸强度校核 ................................................................................... 41 5.2 制动主缸的设计计算 ......................................................................................... 42

5.2.1 制动主缸直径与工作容积的计算 ........................................................... 42 5.2.2 制动主缸强度校核 ................................................................................... 42 5.3 制动踏板力与踏板行程 ..................................................................................... 43 5.4 制动液的选择和使用 ......................................................................................... 44

5.4.1 制动液的主要性能要求 ........................................................................... 44 5.4.2 制动液的分类 ........................................................................................... 45 5.4.3 制动液选用注意事项： ........................................................................... 46

总 结 ......................................................................................................................... 47 参 考 文 献 ....................................................................................................................... 48 致 谢 ......................................................................................................................... 49