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某轻型汽车循环球式动力转向器总成设计
摘 要
机械转向系的能量来源是人力，所有传力件都是机械的，由转向操纵机构（方向盘）、转向器、转向传动机构三大部分组成。其中转向器是将操纵机构的旋转运动转变为传动机构的直线运动（严格讲是近似直线运动）的机构，是转向系的核心部件。
动力转向系除具有以上三大部件外，其最主要的动力来源是转向助力装置。由于转向助力装置最常用的是一套液压系统，因此也就离不开泵、油管、阀、活塞和储油罐，它们分别相当于电路系统中的电池、导线、开关、电机和地线的作用。
转向器（也常称为转向机），是完成由旋转运动到直线运动（或近似直线运动）的一组齿轮机构，同时也是转向系中的减速传动装置。历史上曾出现过许多种形式的转向器，目前较常用的有齿轮齿条式、蜗杆曲柄指销式、循环球－齿条齿扇式、循环球曲柄指销式、蜗杆滚轮式等。其中第二、第四种分别是第一、第三种的变形形式，而蜗杆滚轮式则更是少见。
循环球式转向器目前在国内外汽车上是引用较多的一种结构形式。循环球式转向器中一般有两级传动副，第一级是螺杆螺母传动副，第二级一般采用齿条齿扇传动副。循环球式转向器由螺杆、螺母、钢球和导管、齿条、齿扇构成。由方向盘传动带动螺杆传动，通过钢球将力传给螺母，螺母将沿轴向移动。同时由于摩擦力的作用，所有钢球在螺杆和螺母内的滚道流动，形成“球流”。钢球在螺母内绕行两周后，流出螺母而进入导管，再由导管流回螺母通道内，故在转向器工作时，两列钢球只是在各自的封闭通道内循环，而不会脱出。螺母的轴向移动，通过齿条和齿扇，带动摇臂轴转动, 摇臂轴转动带动汽车转向桥（一般是前桥）上的车轮（转向轮）相对于汽车纵轴线偏转一定角度，完成汽车转向。上述工作原理，循环球式转向器的正向传动效率很高（最高可达90~95%），故操纵轻便，使用寿命长。同时其逆向传动效率也很高，随着道路行驶条件的改善，“打手”的现象明显减少，并且循环球式转向器具有啮合平稳、刚性好、转向轻便、灵活等特点，所以得到了广泛的应用。
该设计在循环球式动力转向器的结构及工作原理进行分析的基础上，采用两级传动副，螺杆、钢球、螺母传动副以及齿扇、螺母传动副完成了某轻型汽车循环球式动力转向器机械传动部分的结构设计。其中包括螺杆螺母传动装置、间隙调整装置、转向摇臂轴、转向螺母、转向螺杆、转向器前、后壳体等零件的设计，同时还对其进行了相关的校核工作。经过校核计算及其理论分析，该循环球式动力转向器能够满足相关规范及工作要求。

关键词　 动力转向器；设计；强度校核
The Design of A Light Vehicle Power Steering Gear
Abstract
Mechanical steering system is the energy source of manpower, all of the pieces are all-mechanical, to manipulation by institutions (steering wheel), steering gear, the transmission mechanism to three major components. Which is the steering gear control the rotational movement into the transmission line Movement (strictly speaking is similar to linear motion), is the shift of the core components.
Power steering with the exception of the above three major components, its main power source is the power steering unit. As power steering unit is the most commonly used a hydraulic system, so it can not be separated from pump, tubing, valves, pistons and storage tanks, each the equivalent circuit system of batteries, wires, switches, motors and the role of ground .
Steering Gear (often known as the Steering), the rotation is completed by the movement to the straight-line movement (or similar linear motion), a group of gears, but also to the slowdown of the transmission device. History-there had been various forms of steering gear, the gear is more commonly used rack-and worm-crank that sell, recycling the ball - rack-tooth fans, circulating that the ball crank pins, such as worm-wheel. The second, fourth, respectively is the first, third form of the deformation, and the worm wheel-is even more rare is.
The current cycle of ball-type steering gear in the car at home and abroad is quoted on a more structural form. Cycle-ball steering gear in the transmission generally have two deputy, is the first-class screw nut transmission Deputy, the second-class general use of rack gear transmission of fans. Cycle-ball steering gear by the screw, nut, Ball and catheter, rack, a fan gear. Screw driven by the steering wheel drive transmission, power will pass through the ball nut, nut along the axial movement. As the role of friction at the same time, all the ball in the screw and nut Raceway flows, a "ball flow." Ball in the nut within two weeks after the bypass, nuts and outflow into the catheter and then return catheter nut channel, the work of the steering gear, two ball only in their respective channels within the closed circle, and will not emerge. Nut axial movement, through the rack and gear fan, driven rocker shaft rotation, rotation axis rocker driven car to the bridge (the former general Bridge) on the wheel (steering wheel) car vertical axis relative to a certain angle of deflection line, To complete the car. The above principle, recycling the ball forward for the steering gear transmission efficiency (up to 90 ~ 95%), the manipulation of light, long life. At the same time reverse its transmission efficiency is also very high, with the road conditions improve, "hatchet man" of significantly reduced, and cycle-ball steering gear meshing with a smooth, rigid, and to light, flexible, and other characteristics, has been widely used .
The design of the ball in the circle of the power steering gear structure and working principle on the basis of an analysis by two deputy transmission, screw, Ball, vice and transmission gear nut fan, nut transmission of light vehicles completed a cycle of ball - Power Steering mechanical transmission part of the structural design. Including screw nut drives, gap adjustment devices, to rocker shaft, to nut, screw shift, steering gear before and after the shell and other parts of the design, while its verification of the relevant work. After checking calculations and theoretical analysis, the ball-cycle power steering gear to meet the relevant standards and job requirements.

Keywords  power steering gear；design；intensity checkup
目录
摘要 I
Abstract II
第1章 绪论 1
1.1 课题研究的意义 1
1.2 国内外研究现状 1
1.3 转向器的发展 2
1.4循环球式动力转向器的概要 3
1.5转向系的检修 5
1.6设计的要求 8
第2章 循环球式转向器的设计方案 9
2.1循环球式转向器设计方案的分析 9
2.2转向器工作过程详解 10
2.3循环球式转向器的结构设计 14
第3章 螺杆、钢球和螺母传动副的设计 16
3.1气体增压泵汽缸组件的设计计算 16
3.2主要尺寸参数的确定 17
3.2.1阿克曼几何学 17
3.2.2最小转弯半径  17
3.2.3转向系的效率 18
3.2.4转向系的角传动比与力传动比 18
3.2.5钢球中心距D、螺杆外径D1和螺母内径D2 21
3.2.6钢球直径d及数量n 21
3.2.7滚道截面 22
3.2.8接触角θ 22
3.2.9螺距P和螺旋线导程角α0 22
3.2.10工作钢球圈数W 22
3.2.11导管内径d1 23
3.2.12转向器的角传动比 23
3.3钢球与滚道之间的强度校核 24
第4章 齿条、齿扇传动副的设计 25
4.1齿条、齿扇传动副的结构设计 25
4.2主要尺寸参数的确定 25
4.2.1齿扇模数m 25
4.2.2转向摇臂轴直径  25
4.2.3齿扇压力角 和切削角  26
4.2.4齿扇宽度B 26
4.3间隙调整装置的设计 26
4.3.1间隙调整装置的工作原理 26
4.3.2间隙调整装置的结构设计 26
4.4齿扇齿的强度校核 27
结论 28
致谢 29
参考文献 30
附录 31