湖南工业大学本科毕业设计（论文）
ABSTRACT
With the rapid development of automobile industry, it as a key part of the automobile steering system has also been developed mighty wave crashing on shore type. From a purely mechanical steering system to the development of power system. This paper carriers on the design to the small tourist bus steering system.
In this paper, the performance parameters of steering system requirement, design of steering trapezoid arrangement, as well as the recirculating ball type steering gear design as the main line, of the design and check of the steering system, the steering system structure system, performance requirement.
This paper first introduces the structure, steering system requirements is selected. Then determine the performance parameters of steering system, mainly in the steering system is (inverse) efficiency, steering force (angle) transmission ratio, mainly engaging characteristics angular gear ratio and steering trapezoid, as the main line and the steering transmission structure; finally to design for the recirculating ball type.
Due to the steering system for driving safety is essential, steering system design has become a key topic of automobile industry and the steering trapezium design are constantly improving, innovation change.
Keywords: recirculating ball steering gear, steering, steering system is efficiency, meshing characteristics
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湖南工业大学本科毕业设计（论文）
目 录
第1章 绪论 ............................................................................................................. 1
1.1 转向系的发展与现状 ............................................................................................. 1 1.1.1 机械式转向系统 ............................................................................................. 1 1.1.2 液压助力式转向系统 ..................................................................................... 1 1.1.3 电液助力式转向系统 ..................................................................................... 1 1.1.4 电动助力式转向系统 ..................................................................................... 2 1.1.5 线控转向系统 .................................................................................................. 2 1.2 转向系发展趋势 ...................................................................................................... 3
第2章 转向系统的组成与要求 ...................................................................... 4
2.1 转向系的组成.................................................................................................. 4 2.1.1 机械转向系统.......................................................................................... 4 2.1.2 动力转向系统.......................................................................................... 4 2.2转向系的基本要求........................................................................................... 5
第3章 转向系选取.............................................................................................. 7
3.1转向操纵机构 ........................................................................................................... 7 3.2转向传动机构 ........................................................................................................... 7 3.3转向器 ........................................................................................................................ 7 3.3.1转向器的传动效率及可逆程度 .................................................................... 8 3.3.2转向器角传动比iw .......................................................................................... 8 3.3.3转向器传动间歇 ............................................................................................... 9 3.4动力转向系统 ........................................................................................................... 9 3.4.1液压助力式转向系统 ...................................................................................... 9 3.4.2电液助力式转向系统 ...................................................................................... 9 3.4.3电动助力式转向系统 ...................................................................................... 9
第4章 转向系统主要性能参数确定 ........................................................... 10
4.1转向系效率 .............................................................................................................. 10 4.1.1转向系正效率4.1.2转向系逆效率
........................................................................................... 10 ........................................................................................... 10
4.2转向系传动比 ......................................................................................................... 11 4.2.1转向系力传动比 ......................................................................................... 11
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湖南工业大学本科毕业设计（论文）
4.2.2转向系角传动比4.2.3转向器角传动比
...................................................................................... 11 ........................................................................................ 11
.............................................................................. 11
4.2.4转向传动机构角速度
4.3转向系力传动比与角传动比的关系 .................................................................. 11 4.4转向传动系传动比的计算 ................................................................................... 12 4.4.1转向阻力矩
计算 ....................................................................................... 12
计算 ...................................................... 13
4.4.2转向系力传动比及角传动比
4.5转向系传动副的啮合间隙特性 ........................................................................... 13 4.5.1转向器的啮合特性 ........................................................................................ 13 4.5.2转向盘自由行程 ............................................................................................. 14 4.5.3转向盘总回转圈数n的计算 ....................................................................... 14
第5章 转向传动机构设计.............................................................................. 15
5.1转向梯形方案分析................................................................................................. 15 5.1.1整体式转向梯形 ............................................................................................. 15 5.1.2断开式转向梯形 ............................................................................................. 15 5.1.3转向梯形机构尺寸确定................................................................................ 16 5.1.4转向梯形的优化 ............................................................................................. 17 5.2纵拉杆 ...................................................................................................................... 18 5.2.1纵拉杆强度校核 ............................................................................................. 18 5.3横拉杆 ...................................................................................................................... 19
第6章 循环球式转向器设计 ......................................................................... 20
6.1转向系计算载荷的确定 ........................................................................................ 20 6.1.1循环球式转向器 ............................................................................................. 21 6.2主要尺寸参数选取................................................................................................. 21 6.2.1钢球中心距D .................................................................................................. 22 6.2.2螺杆内外径选取 ............................................................................................. 22 6.2.3工作钢球圈数W .............................................................................................. 23 6.2.4钢球直径与数量的选取................................................................................ 23 6.2.5滚道截面 .......................................................................................................... 24 6.2.6接触角 .............................................................................................................. 24 6.2.7螺距P与倒程角
....................................................................................... 25
6.3转向器计算和校核................................................................................................. 25 6.3.1钢球滚道间接触应力σ ................................................................................ 25
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湖南工业大学本科毕业设计（论文）
6.3.2齿扇齿的弯曲应力 .................................................................................. 26
第7章 动力转向系统 ....................................................................................... 27
7.1液压缸设计 .............................................................................................................. 27 7.1.1液压缸作用力F .............................................................................................. 27 7.1.2液压缸内径D .................................................................................................. 27 7.1.3液压缸长度 ..................................................................................................... 27 7.1.4活塞运动速度 ................................................................................................. 27 7.2转向油泵 .................................................................................................................. 28 7.3管路系统 .................................................................................................................. 28 7.3.1流速 .................................................................................................................. 28 7.3.2硬管 .................................................................................................................. 28 7.3.3软管 .................................................................................................................. 29 7.3.4油箱 .................................................................................................................. 29
结论 ............................................................................................................................ 30 参考文献 ................................................................................................................... 31 致谢 ............................................................................................................................ 32
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湖南工业大学本科毕业设计（论文）
第1章 绪论
1.1 转向系的发展与现状
改革开放以来，我国汽车工业得到长足发展。作为汽车关键部位的转向系统也得到迅猛发展，转向系统已由纯机械式转向系向助力式转向系发展。助力式转向系由于转向操纵轻便灵活，能够吸收路面对车轮冲击等优点已在汽车制造业中被普遍采用。
汽车转向系经历100多年的发展历史，经历了机械式转向系统——液压助力式转向系统——电液助力式转向系统——电动助力式转向系统——线控转向系统。其中助力式转向系统得到了广泛的使用。
1.1.1 机械式转向系统
机械式转向系统应用较多，现在所有的转向系统都要求有机械转向系统以保证转向的安全可靠性。机械式转向系统以人力为动力来源，所有传递力的零件都是机械的，它由转向操纵机构、转向器和转向传动机构组成。
转向系的力传动比和角传动比成反比关系。当力传动比大时，转向省力，转向轻便性好但是转向灵敏性就变差；当角传动比大时，转向灵敏性好了，但转向需要很大的力，转向轻便性达不到要求。因此机械式转向系在同时满足转向轻便性和转向灵敏性的要求是十分有限的，这也制约了机械式转向系的发展。随着转向系的发展，出现了助力式转向系统，这在一定程度上缓解了转向轻便性和灵敏性这一矛盾。
1.1.2 液压助力式转向系统
液压助力式转向系统是在机械转向系统的基础上增加液压系统发展起来的。它以发动机的动力作为油泵的能量来源，用液压力增加驾驶员的操纵力。因此可以在一定程度上减小转向系的力传动比，增大角传动比，从而缓解转向“轻”与“灵”的矛盾。
随着社会经济的不断发展，人们对速度的要求越来越高，汽车速度也在不断的提高，液压助力式转向系的不足开始显现出来。汽车在高速运行或者低速运行和停车时，很难保证驾驶员有适度的手感；同时汽车的燃油经济性变差；停车时无法提高助力等都制约了其发展。
1.1.3 电液助力式转向系统
电液助力式转向系统在液压系统的基础上，用电机取代发动机驱动油泵的方式发展而来的。它通过电磁阀控制助力油压随车速变化而变化，在汽车低速或急转弯时转向轻便；在高速行驶时有较好的手感。
目前电液助力式转向系统在轿车上得到了广泛的运用。但是它结构更加复杂，价
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