履带拖拉机变速器改进设计Ⅳ(有cad图).doc

履带拖拉机变速器改进设计Ⅳ

摘要

随着农业的不断进步发展，农业生产机械化、规模化及生产资料和农田建设材料等各种物资运输量越来越大，农民越来越需要拖拉机的帮助，因此，农用拖拉机的发展前景很广阔，会有较大的发展。

满足拖拉机的动力性和经济性指标，这与变速器的档数、传动比的范围和各档传动有关。拖拉机工作的道路条件越复杂、比功率越小，变速器的传动比

范围越大。变速器与主减速器及发动机参数作优化配置，可得到良好的动力性和经济性。

变速器的结构对动力性，经济性，操纵的可靠性与轻便性，工作噪声等

都有直接影响。变速器主要用来改变发动机传到驱动轮上的转矩和转速，目

的是在起步、爬坡、转弯、加速等各种行驶工况下，获得不同的牵引力和速

度，同时使发动机在最有利的工况下范围工作，设有空档和倒档。

本次设计按照传统设计方法，本着半经验半理论的设计原则通过类比法确定

方案，参照已有车型变速器结构，最后以机械零件的强度和刚度理论对确定的

形状和尺寸进行必要的计算和校核，以满足约束条件，进而缩短设计周期，降低

设计成本。

关键词：变速器，传动比，设计，计算，校核

TRACKED TRACTOR TRANSMISSION IMPROVED

DESIGNⅣ

ABSTRACT

With the continuous progress of agricultural development,agricultural production mechanization, the scale of the means of production and agricultural

land and building materials and other goods traffic increasing, more and more farmers need the help of tractors, therefore, farm tractors development prospects

are broad, there will be greater development.

Tractors to meet the power and economic indicators, and transmission of

the file, the transmission ratio of the scope and the transmission of the file. Tractor work of the road conditions more complex than the smaller power, the transmission of the transmission ratio greater. Reducer and the main transmission and engine parameters to optimize the allocation and availability of power and good economy.

In order to make it come true that the transmission is adapted to the engine and its structure is sound, I pay close attention to the development of the clutch transmission shaft and collectivity arranging designers in my design,and have a repeating discussion with them .

For shifting gear steadily , fourth and third gear have synchrotron ,and in consideration of the simplicity and reliability .According to the traditional mean

of design ,part experience and theory and analogism ,the blue print come into

being .by virtue of tradition transmission I verify the size of element which have

been chosen, according to mechanical theory, in consideration of the qualification bringing down the cost and cycle time.

KEY WORD：Transmission, transmission ratio, design, calculations, checking

符号说明

A 中心距

D 直径

E 弹性模量

i g 传动比

f 挠度

转角

M 弯矩

m 汽车总质量kg

g 重力加速度N/kg

道路最大阻力系数

max

r r 驱动轮的滚动半径mm T

e max 发动机最大扭矩N· m i 0 主减速比

汽车传动系的传动效率

i

gI 一档传动比

G2 汽车满载载荷N

路面附着系数

K A 中心距系数

m t 直齿轮模数

齿轮压力角°

斜齿轮螺旋角°b 齿轮宽度mm

Z x 齿轮齿数

齿轮弯曲应力MPa W

齿轮接触应力MPa j

F t 齿轮所受圆周力N