齿轮是能互相啮合的有齿的机械零件,它是机械传动领域的一个重要组成部分。在2000多年前的中国就已经出现了齿轮的应用，从早期的指南车到明初的水车，再经过近现代世界各国工业化的日益发展，各种各样的齿轮机构也随之出现，并向着高强度、高效率、高载荷和高精度的方向发展。此课题正是基于封闭式齿轮试验台，检测一齿轮箱的传动效率与强度的综合性能，以实现快捷有效地对齿轮性能进行分析，获得符合设计要求的齿轮。本文先对齿轮箱作传动效率试验，再对齿轮作疲劳试验与有限元分析计算，综合两方面结果对齿轮传动效率与强度性能进行研制。
关键词：齿轮；效率；强度；有限元分析；研制

Abstract
Gear is to mesh each other toothed machine part, It is an important part in the field of mechanical transmission. In more than 2000 years ago in China has been the application of the gear, from the early south to the Ming dynasty in the early of the water wheel, after again the development of the modern industrialized world, all kinds of gear has been invented, and toward a high strength and high precision, high efficiency, high load direction development. This topic is based on the enclosed gear test bench, detection of a gear box transmission efficiency and strength of comprehensive performance, in order to realize fast and effectively on gear performance is analyzed, comply with the design requirements of gear. This article will first to the gearbox transmission efficiency test, then on gear for fatigue test and finite element analysis and calculation, results two respects strength of gear transmission efficiency and the performance is developed.
Key words：Gear; efficiency; strength; the finite element analysis; to develop

目录
摘要
Abstract
第一章绪论 3
1.1齿轮的出现及其发展 4
1.2研究齿轮传动性能的意义与方法 5
1.3本次课题研究的主要内容 6
1.4试验方案的选择 6
1.5本章小结 7
第二章实验台测试控制系统及实验部件的联接关系 7
2.1.测试控制系统组成 8
2.2测试系统各部件的组成、结构与联接 8
2.2.1动力源的组成、结构与联接 8
2.2.2加载装置的组成、结构与联接 9
2.2.3圆柱齿轮组的组成与结构 10
2.3本章小结 11
第三章实验台器材的选用与安装说明 12
3.1实验台器材的选用 12
3.1.1传动方案拟定 12
3.1.2电机的选择 12
3.1.3扭矩传感器的选用与特性 13
3.1.4联轴器的选择 14
3.1.5主动轴与其轴承的选择 14
3.1.6键联接的选择及校核计算 15
3.1.7齿轮箱箱体、箱盖及附件的选用与计算 16
3.2齿轮传动效率实验台的安装说明 17
3.2.1按图所示安装效率实验台。 17
3.2.2安装及调试 18
3.3本章小结 19
第四章齿轮传动效率与强度试验综合实验过程与结果 20
4.1齿轮传动效率及其测定 20
4.2齿轮传动效率的计算 23
4.3齿轮疲劳的形成及表现 23
4.3.1轮齿折断 24
4.3.2齿面点蚀 24
4.3.3齿面胶合 25
4.3.4齿面磨损 25
4.3.5齿面塑性变形 26
4.4齿轮的强度要求与计算 26
4.4.1齿轮受力分析 26
4.4.2齿面接触疲劳强度计算 28
4.5本章小结 32
第五章齿轮三维模型建立与应力分析 33
5.1齿轮三维模型的建立 33
5.2应力分析 33
5.2.1网格的建立 33
5.2.2应力分析 34
5.3本章小结 36
第六章结论 37
参考文献 38
致谢
附录一：JCZS-Ⅱ机械传动性能综合实验台组件清单（单位：件/套）
附录二：齿轮常用材料及其机械性能

第一章绪论
1.1齿轮的出现及其发展
齿轮的出现及运用历史悠久，最古老的齿轮运用历史可追溯到3000~5000年以前，几乎和人类文明史同步。随着科技的发展和近代工业革命的兴起，齿轮作为机械设备的重要传动装置，得到了广泛的应用和发展。为了适应高速、重载、小型、轻量以及大传动比和其他运动特性的要求，各种各样新型的齿轮传动机构不断出现。

内容简介：: 浙江理工大学机械与自动控制学院本科生毕业设计（论文）质量监控表机械与自动控制学院本科生毕业设计（论文）修改意见表姓名梅璐学号B09300419指导教师唐浙东班级09机制（4）是否二辩论文题目序号答辩委员会提出的修改意见（答辩成员执笔填写，不够另行附页）12345678910 填写人员签字：日期：整改结论导师签名：日期：说明：1 每位学生答辩时，由答辩组成员填写答辩委员会的修改意见，并签字。2 答辩结束后，本表返还给导师，由导师监促学生整改，学生修改完毕后由导师逐条确认修改情况并签名，再交给答辩组长签收，将本表和毕业设计(论文)资料一起交学院存档。附件七-4:浙江理工大学毕业设计（论文）成绩评定表毕业设计（论文）题目姓名学号专业指导教师评分（35%）评阅教师评分（35%）答辩小组评分（30%）合计答辩委员会评语：成绩等级：学院答辩委员会主任签字：年月日（学院公章）附件七-1:浙江理工大学毕业设计（论文）指导教师评语表毕业设计（论文）题目姓名学号专业文献综述（10%）毕业设计（论文）（60%）工作表现（10%）其他（20%）合计分数指导教师评语：指导教师（签章）年月日注：其他是指开题报告、外文翻译及毕业实习报告等。1附件七-3:浙江理工大学毕业设计（论文）答辩小组评语表毕业设计（论文）题目姓名学号专业毕业设计（论文）（40%）答辩情况（60%）合计分数答辩小组评语：答辩小组组长（签章）年月日附件五：浙江理工大学毕业设计（论文）答辩记录表日期学院专业 / 班级学生指导教师毕业设计（论文）题目答辩时间答辩地点答辩记录：答辩记录人：年月日答辩组成员签字：年月日14附件七-2:浙江理工大学毕业设计（论文）评阅教师评语表毕业设计（论文）题目姓名学号专业选题（10%）文献综述（10%）外文翻译（10%）毕业设计（论文）（70%）合计不分数评阅教师评语：评阅教师（签章）年月日???????????B1GB1096-79?8x22?ZS2-11-1?01?-06-5-06-6A-06-4-06-3A-06-2-11-2A-06-905030204060708? ?HT180?HT180HT180?A3454545?x20?GB97.1-85GB5783-86GB97.1-85ZS2-06-10GB276-GB5783-86B3B2B4B6B509?浙江理工大学本科毕业设计（论文）任务书梅璐同学09机械设计制造及其自动化（4）班现下达毕业设计（论文）课题任务书，望能保质保量地认真按时完成。课题名称齿轮传动效率与强度试验综合试验台研制主要任务与目标伴随着工业革命以来,齿轮的应用也越来越广泛,尤其是在人们生活工作越来越工业化的今天,齿轮的研究利用也越来越精细化,研究其传动效率和强度的试验也需要与时俱进。齿轮传动效率与强度试验平台是为了方便研究齿轮的工作特性而产生的一种实验平台，它通过电机的输入转速转矩和经过齿轮传动后的输出转速转矩之比，再通过计算机的显示器和打印机最终得到输出结果即为其传动效率；同时利用该试验台将两对试验齿轮经由加载施加载荷进行长时间试验直至其发生疲劳破坏来测得齿轮疲劳曲线。本课题重点完成控制电机及控制方法选择，相应传感器等零件的选择组装，不同的组装得到的结果不尽相同。主要任务是：1、了解齿轮传动效率与强度试验综合试验台研制研究目的，理解各传动部件的结构性能，确定完整实验系统总体方案。2、综合试验台的机械装配图以及各主要零件的加工图。3、不同的传动件和支撑件组装出不同的传动系统，使系统的传动效率也不同。4、相应的电动机、传感器等组件的型号选定。5、实验指导书编制。目标：确定完整可行的系统总体方案，了解该试验台的各个零件的组装，相应传感器，制动器等的选择，能使用有限元法对齿轮疲劳曲线进行分析计算等。主要内容与基本要求主要设计内容有：1、了解齿轮传动效率与强度试验综合试验研制平台研制目的及其发展。确定完整实验系统总体方案。 2、相关电机功率和传感器等零件的的选定。 3、了解掌握有限元法对课题结果的分析计算。基本要求：要求学生掌握：零件测绘技术、计算机网络通信技术、cad及Proe等软件绘图。按照课题内容，完成毕业设计要求的各种文档，包括文献综述、开题报告、外文翻译及毕业设计论文等。严格按照进度安排，保质保量完成所承担的任务；遵守实验室规定。主要参考资料及文献阅读任务查阅与课题有关的文献（论文、书籍或手册等）不少于10篇（部），写出符合要求的文献综述报告。主要参考文献如下：1 孙恒，陈作模，葛文杰.机械原理（第七版）M.北京：高等教育出版社，2006：77.2 何亚银考虑外加负载影响的机构动平衡研究J机械设计，2009，26(2)：38393 唐锡宽，金德闻.机械动力学M.北京：高等教育出版社，1983：40-41.4 范垂本.齿轮的强度和试验.机械工业出版社，1979:21-29.5 全国齿轮标准化技术委员会.GB/Z6431.2-2003圆柱齿轮、圆锥齿轮承载能力计算方法S.北京标准化出版社，2003.6 成大先等编著.机械设计手册.第3卷.第四版.北京：化学工业出版社，20027 庞学慧，武文革. 互换性与测量技术基础。北京：电子工业出版社，2007.8 梁桂明，朱向贵，黄希忠.齿轮技术的发展趋势J.中国机械工程，1995,69 Paul N.Liang,Deane Jaeger.Method for determing the balancer condition of a balanced engineP.United states patent:US 6,510,732 B1,Jan.28,2003.10 J.Castro,J.seabra.Global and local analysis of gear scuffing tests Using a mixed film lubrication model.Tribiol Int (2007),doi:10.1016/ j.triboint,2007:1-12P外文翻译任务阅读2篇以上（10000字符左右）的外文材料，完成2000汉字以上的英译汉翻译。英文文献参考如上：计划进度：时间工作内容负责人2012.9.20分管院领导作毕业设计动员（教师）分管院长2012.9.20-2012.10.08毕业设计相关文件及规定学习、优秀毕业设计（论文）交流；确定教师所带人数、完成选题表、所级题目审核各系系主任2012.10.09-2012.10.15教学委员会题目审核、按专业毕业设计动员（学生）分管院长、学生线2012.10.16-2012.10.22学生选题各系系主任、各班班长2012.10.23-2012.10.29各所根据学生选题情况进行平衡调整，确定指导教师及各课题学生，上交毕业设计（论文）信息表。各系系主任2012.10.30-2012.11.06教师填写毕业设计任务书、确定外文阅读与翻译资料，并下达毕业设计任务指导教师2012.11.07-2012.12.27学生毕业设计调研，完成开题报告、文献综述、外文资料阅读、翻译任务指导教师2012.12.28-2013.01.10学生开始开题报告、文献综述及外文翻译初稿，指导教师审阅，提出修改意见指导教师2013.01.10-2013.01.16各系进行开题报告提交审核各系系主任2013.01.16-2013.01.19本周开始，指导教师应对所指导的每位学生进行考核登记毕业设计前期检查：任务书、综述报告、开题报告、外文翻译院教学委员会、院督导组2013.02.27-2013.04.04按毕业设计任务书要求进行毕业设计指导教师2013.04.05-2013.04.11毕业设计中期检查：教师指导情况、学生完成情况、表格与记录的填写情况院教学委员会、院督导组2013.04.12-2013.05.09学生完成课题设计，提交毕业设计（论文）指导教师2013.05.10-2013.05.15指导教师完成所指导学生的毕业设计（论文）的审阅，写出评语，评出成绩；评议小组分组审阅，写出评语，评定成绩指导教师、各系评议组2013.05.20-2013.05.22学院分组进行答辩，由答辩小组给出评语及成绩答辩小组2013.05.27-2013.05.28二次答辩答辩小组2013.05.30-2013.05.31进行成绩综合评定，上报学生毕业设计（论文）成绩教学委员会实习地点指导教师签名年月日系意见系主任签名：年月日学院盖章主管院长签名：年月日4外文翻译毕业设计题目：齿轮传动效率与强度试验综合实验台研制原文1：Gears and gear drive译文1：齿轮和齿轮传动原文2：Fatigue Abstracts译文2：疲劳摘要Gears and gear driveGears are the most durable and rugged of all mechanical drives. They can transmit high power at efficiencies up to 98% and with long service lives. For this reason, gears rather than belts or chains are found in automotive transmissions and most heavy-duty machine drives. On the other hand, gears are more expensive than other drives, especially if they are machined and not made from power metal or plastic. Gear cost increases sharply with demands for high precision and accuracy. So it is important to establish tolerance requirements appropriate for the application. Gears that transmit heavy loads or than operate at high speeds are not particularly expensive, but gears that must do both are costly. Silent gears also are expensive. Instrument and computer gears tend to be costly because speed or displacement ratios must be exact. At the other extreme, gears operating at low speed in exposed locations are normally termed no critical and are made to minimum quality standards. For tooth forms, size, and quality, industrial practice is to follow standards set up by the American Gear Manufactures Association (AGMA). Tooth form Standards published by AGMA establish gear proportions and tooth profiles. Tooth geometry is determined primarily by pitch, depth, and pressure angle. Pitch：Standards pitches are usually whole numbers when measured as diametral pitch P. Coarse-pitch gearing has teeth larger than 20 diametral pitch usually 0.5 to 19.99. Fine-pitch gearing usually has teeth of diametral pitch 20 to 200.Depth: Standardized in terms of pitch. Standard full-depth have working depth of 2/p. If the teeth have equal addenda(as in standard interchangeable gears) the addendum is 1/p. Stub teeth have a working depth usually 20% less than full-depth teeth. Full-depth teeth have a larger contract ratio than stub teeth. Gears with small numbers of teeth may have undercut so than they do not interfere with one another during engagement. Undercutting reduce active profile and weakens the tooth.Mating gears with long and short addendum have larger load-carrying capacity than standard gears. The addendum of the smaller gear (pinion) is increased while that of larger gear is decreased, leaving the whole depth the same. This form is know as recess-action gearing.Pressure Angle: Standard angles are and . Earlier standards include a 14-pressure angle that is still used. Pressure angle affects the force that tends to separate mating gears. High pressure angle decreases the contact ratio (ratio of the number of teeth in contact) but provides a tooth of higher capacity and allows gears to have fewer teeth without undercutting.Backlash: Shortest distances between the non-contacting surfaces of adjacent teeth . Gears are commonly specified according to AGMA Class Number, which is a code denoting important quality characteristics. Quality number denote tooth-element tolerances. The higher the number, the closer the tolerance. Number 8 to 16 apply to fine-pitch gearing.Gears are heat-treated by case-hardening, through-hardening, nitriding, or precipitation hardening. In general, harder gears are stronger and last longer than soft ones. Thus, hardening is a device that cuts the weight and size of gears. Some processes, such as flame-hardening, improve service life but do not necessarily improve strength. Design checklistThe larger in a pair is called the gear, the smaller is called the pinion.Gear Ratio: The number of teeth in the gear divide by the number of teeth in the pinion. Also, ratio of the speed of the pinion to the speed of the gear. In reduction gears, the ratio of input to output speeds.Gear Efficiency: Ratio of output power to input power. (includes consideration of power losses in the gears, in bearings, and from windage and churning of lubricant.)Speed: In a given gear normally limited to some specific pitchline velocity. Speed capabilities can be increased by improving accuracy of the gear teeth and by improving balance of the rotating parts.Power: Load and speed capacity is determined by gear dimensions and by type of gear. Helical and helical-type gears have the greatest capacity (to approximately 30,000 hp). Spiral bevel gear are normally limited to 5,000 hp, and worm gears are usually limited to about 750 hp.Special requirementsMatched-Set Gearing: In applications requiring extremely high accuracy, it may be necessary to match pinion and gear profiles and leads so that mismatch does not exceed the tolerance on profile or lead for the intended application.Tooth Spacing: Some gears require high accuracy in the circular of teeth. Thus, specification of pitch may be required in addition to an accuracy class specification.Backlash: The AMGA standards recommend backlash ranges to provide proper running clearances for mating gears. An overly tight mesh may produce overload. However, zero backlash is required in some applications.Quiet Gears: To make gears as quit as possible, specify the finest pitch allowable for load conditions. (In some instances, however, pitch is coarsened to change mesh frequency to produce a more pleasant, lower-pitch sound.) Use a low pressure angle. Use a modified profile to include root and tip relief. Allow enough backlash. Use high quality numbers. Specify a surface finish of 20 in. or better. Balance the gear set. Use a nonintegral ratio so that the same teeth do not repeatedly engage if both gear and pinion are hardened steel. (If the gear is made of a soft material, an integral ratio allows the gear to cold-work and conform to the pinion, thereby promoting quiet operation.) Make sure critical are at least 20% apart from operating speeding or speed multiples and from frequency of tooth mesh.Multiple mesh gearMultiple mesh refers to move than one pair of gear operating in a train. Can be on parallel or nonparallel axes and on intersection or nonintersecting shafts. They permit higer speed ratios than are feasible with a single pair of gears .Series trains:Overall ratio is input shaft speed divided by output speed ,also the product of individual ratios at each mesh ,except in planetary gears .Ratio is most easily found by dividing the product of numbers of teeth of driven gears by the product of numbers of teeth of driving gears.Speed increasers (with step-up rather than step-down ratios) may require special care in manufacturing and design. They often involve high speeds and may creste problems in gear dynamics. Also, frictional and drag forces are magnified which, in extreme cases , may lead to operational problems.Epicyclic Gearing:Normally, a gear axis remains fixed and only the gears rotates. But in an epicyclic gear train, various gears axes rotate about one anther to provide specialized output motions. With suitable clutchse and brakes, an epicyclic train serves as the planetary gear commonly found in automatic transmissions. Epicyclic trains may use spur or helical gears, external or internal, or bevel gears. In transmissions, the epicyclic (or planetary) gears usually have multiple planets to increase load capacity. In most cases, improved kinematic accuracy in a gearset decreases gear mesh excitation and results in lower drive noise. Gearset accuracy can be increased by modifying the tooth involute profile, by substituting higher quality gearing with tighter manufacturing tolerances, and by improving tooth surface finish. However, if gear mesh excitation generaters resonance somewhere in the drive system, nothing short of a “perfect” gearset will substantially reduce vibration and noise. Tooth profiles are modified to avoid interferences which can result from deflections in the gears, shafts, and housing as teeth engage and disendgage. If these tooth interferences are not compensated for by profile modifications, gears load capacity can be seriously reduced. In addition, the drive will be noisier because tooth interferences generate high dynamic loads. Interferences typically are eliminated by reliving the tooth tip, the tooth flank, or both. Such profile modifications are especially important for high-load , high-speed drives. The graph of sound pressure levelvs tip relief illustrates how tooth profile modifications can affect overall drive noise. If the tip relief is less than this optimum value, drive noise increases because of greater tooth interference; a greater amount of tip relief also increase noise because the contact ratio is decreased. Tighter manufacturing tolerances also produce quietier gears. Tolerances for such parameters as profile error, pitch AGMA quality level. For instance, the graph depicting SPL vs both speed and gear quality shows how noise decreases example, noise is reduced significantly by an increase in accuracy from an AGMA Qn 11 quality to an AGNA Qn 15 quality. However, for most commercial drive applications, it is doubtful that the resulting substantial cost increase for such an accuracy improvement can be justified simply on the basis of reduced drive noise. Previously, it was mentioned that gears must have adequate clearance when loaded to prevent tooth interference during the course of meshing. Tip and flank relief are common profile modifications that control such interference. Gears also require adequate backlash and root clearance. Noise considerations make backlash an important parameter to evaluate during drive design. Sufficient backlash must be provided under all load and temperature conditions to avoid a tight mesh, which creates excessively high noise level. A tight mesh due to insufficient backlash occurs when the drive and coast side of a tooth are in contact simultaneously. On the other hand, gears with excessive backlash also are noisy because of impacting teeth during periods of no load or reversing load. Adequate backlash should be provided by tooth thinning rather than by increase in center distance. Tooth thinning dose not decrease the contact ratio, whereas an increase in center distance does. However, tooth thinning does reduce the bending fatigue, a reduction which is small for most gearing systems.齿轮和齿轮传动在所有的机械传动形式中，齿轮传动是一种最结实耐用的传动方式。它们可以传递很大的功率，效率可以达到98%，并且服务年限长。由于具有以上优点，齿轮传动比皮带装置等其它传动方式更常见于自动式传动机构和重载机构中。在另一方面，齿轮比其它传动方案贵得多，特别是精加工齿轮和合金钢材料的。齿轮的制造成本会随便着精度和公差的要求急剧增加。因此，在合适的范围内选一个合理的公差带就显得尤其重要。用于大功率传递和高速传递的齿轮传动系统不是特别的贵，但是用合金钢材料和精加工的齿轮成本比较高。低噪声齿轮机构也很昂贵。精密仪器和电脑里用的齿轮机构住住是相当昂贵的，因为它们对速度和传动比的要求很高。低速的开式传动的被定义为非临界状态，并且以此作为齿轮的最小标准。齿轮的形状、尺寸、性质和工业用途都遵循美国齿轮制造协会所制定的标准。齿形美国齿轮制造协会发布的标准说明齿轮系的传动比分配比例和齿的轮廓。齿的几何形状主要是由节距、齿高和压力角来确定的。节距：标准节距通常都是整数。大节距齿轮的节距直径比它的节距的二十倍还大，一般在0.519.99之间。小节距齿轮的节距直径一在20200之间。齿高：以节距为标准，齿轮的工作齿面高度是全齿高的一半。如果齿轮有相同的齿高那么齿高是节距的倒数。变位齿轮它的工作时的啮合深度通常比它的全齿高少20%，以防止产生根切身。不变位齿轮比变位齿轮的传动比更大。齿数较少的齿轮可能会产生根切，所以大切削深度的齿轮比起它们来在啮合时候齿轮互不影响。减少齿轮的有效齿廓会使齿轮的强度削弱。让变位齿轮和不变位齿轮相啮和能传递比标准齿轮更大的功率。两个个啮合的齿轮当变位齿轮齿高减小时，不变位齿轮向变位后的齿轮深入一些，保证啮合高度不变。这就是众所周知的间歇性齿轮。压力角：压力角通常取和。早期的压力角还包括14-1/2，现在仍然在使用。压力角的大小会影响相啮合齿轮的强度。大的压力角可以减少齿轮在啮合时的齿数，而且利用不变位齿轮还能够传递更大的功率。齿侧间隙：在两个啮合的齿之间非接触最小的那个间隙。齿轮传动系统都严格按照美国齿轮制造协会所制定的等级制造，每个指标都表示齿轮的一项重要性能。特性指数表示齿轮元素的公差，等级数目越高，它越接近于公差。等级35应用于大节距齿轮，816应用于小节距齿轮。齿轮通过热处理提高强度，比如表面硬化、淬火、氮化、回火。一般而言，硬齿面的齿轮系统比软齿面的齿轮系统使用寿命更长更坚固。因而，淬火可以减小齿轮的尺寸和重量。有些处理方式，例如表面淬火可以提高齿轮的使用寿命但是没有必要提高它的强度。齿轮传动系统的校核项目：在一对相啮合的齿轮中，大的那个是从动轮，小的是主动轮。齿数比：大齿轮的齿数除以小齿轮的齿数。同样也是小齿轮的线速度除以大齿轮的线速度。在齿轮减速机构中，是输入速度与输出速度的比值。齿轮传动的效率：齿轮输出功率与输入功率的比值。（包括考虑传动时的功率损失，轴承、联轴器、和润滑的功率损失）在一些给定的齿轮中，节圆线速度是限定的。齿轮传动速率可以通过提高齿轮制造精度、增加回转件的平衡性来提高。负荷速度和传递功率大小受齿轮尺寸和齿轮类型的限制。斜齿轮和斜齿轮系所能传递的功率最大，可以近似达到30000马力、弧齿锥齿轮一般限制在5000马力、蜗轮蜗杆传动限制在大约750马力。工艺要求：齿轮配合：在工艺上要求比较高精度的齿轮系统中，对于防止错齿、齿廓与齿廓接触和从动齿轮的啮合，不会超过规定的范围是很有必要的。齿间隙：有些齿轮对齿廓的精度要求相当高，因此，齿轮的规格等级必须符合所规定的精度等级。无声传动装置：将齿轮传动系统制造得尽可能的静音。为了达到此目的可以有以下多种方法供选择，选择小螺距齿轮来满足负荷状态的要求；在某些特定情况下，可以改变齿轮的啮合次数来使传动声音减小，或者使声音更加低沉以达到静音的目的；用压力角较小和对齿轮根尖都进行过修正的齿轮；允许足够大的齿间隙；采用高的特性指数；保证表面粗糙度在20或者更小；合理分配齿轮系的传动比；采用一个非整数的传动比，那么一样的齿轮就不会重复的啮合如果它们都是硬化钢材料。如果齿轮由软钢制成且传动比为整数，则齿轮必须冷作处理以满足工作的要求，从而实现无声传动。保证速度临界点大于全速运行的20%或者通过增加齿轮啮合次数来成倍增加的转速。齿轮系传动装置是指在一个传动装置中有不只一对齿轮在啮合工作。可以是相互平行或不平行的轴，相交或不相交的轴。在实际应用中，他们可以达到很高的速度比相对于只有一对齿轮啮合的传动装置。串联齿轮系，所有啮合齿轮的传动比都是将输入轴的转速降到输出轴的转速。总的传动比是所有传动比的乘积，行星轮系不适用这种计算方法。这种传动装置的传动比很好计算，就是将每一对啮合齿轮的传动比相乘。增速器在设计和制造方面有特殊的工艺要求。他们通常包括很高的速度还可能有一些齿轮动力学里一些很极端的问题，同样，摩擦力和拉力也包含在里面，在这种情况下还可能进一步导致操作的问题。行星轮系传动：通常在一个传动装置中，齿轮轴线是固定不变的的仅仅是轴上的齿轮在转动。但是在一个行星轮系中，不同的齿轮轴围着太阳轮地轴线转动给特定的输出装置提供动力。行星轮传动再配合离合器和刹车装置，就可以组成一个无级变速的自动驾驶系统。行星轮传动可以用直齿或者斜齿，内齿轮或者外齿轮，或者锥齿轮。在传递过程中，可以通过增加行星轮的个数来达到传递更大功率的要求。在许多情况下, 提高齿轮系中相啮合齿轮的运动精确度可以降低机构运行的噪音。修改齿轮渐开线齿形可以提高齿轮的精确度，用高精度的制造公差来保证高质量的齿轮啮合质量；提高齿面的粗糙度。但是，如果在一个传动系统的某个地方发生振动那么一个“完美”的齿轮机构将会减少振动和噪声。修正齿轮的齿廓可以避免在传动过程中由于偏差、轴的偏移、机壳的不标准而产生干涉。如果齿轮干涉不能通过修正齿廓来消除那么齿轮上的载荷应该减少。当齿轮载荷很大时，机构噪声会更大因为内部传递的齿轮发生了干涉。消除干涉可以通过改变齿高、齿侧间隙或者两者都做。齿轮变位对于重载机构和高速传动机构尤其重要。声音压力水平曲线图可以很形象地说明齿轮变位可以影响齿轮机构的噪声。如果减少的量比最适宜量小的话，那么机构会产生更大的噪声，因为齿轮干涉。减少过多的齿高度噪声也会增强因为接触比例减小了。高制造公差等级的齿轮也可以实现无声传动，那样的公差等级作为齿廓的形位误差可以达到美国齿轮制造协会的质量水平。这个图表描述了速度和齿轮质量对声音压力水平的影响，还有如何减小噪声的方法。当齿轮的精度等级由美国齿轮制造协会规定的11级增加到15级时，噪声明显的减小了。但是对于商业用的传动机构来说，花费这么大的代价在降低噪声上是不划算的，因为还有别的更廉价的方式来降低噪声。以前有个说法，为了防止齿轮干涉两个相啮合的齿轮必须经过修正。齿顶高和齿侧间隙都是很常用的齿廓修正以保证齿轮不发生干涉。齿轮传动系统也需要有适当的齿侧间隙和齿根修正。在设计齿轮机构中，齿侧间隙是评定噪声的一个重要参数。必须有足够的齿侧间隙和合理的载荷、温度状况来防止齿轮的干涉，否则会产生很大的噪声。干涉是由于齿侧间隙不足造成，工作的齿面和不工作齿面同时接触上了。另一方面，过大的齿侧间隙也会产生噪声，因为在齿轮无载荷啮合周期内或回动载荷会对齿轮产生冲击。要获得合理的齿侧间隙，减少齿的个数比增加轴的中心距效果更好。减少齿数不会减少齿轮接触比例，反之增大中心距也不会。但是减少齿数会减小齿轮的挠曲疲劳，这个减小量对一个齿轮系统来说是很小的。Fatigue AbstractsThis section contains abstracts of selected articles, technical reports, dissertations and patents concerned with fatigue. It is prepared in collaboration with Materials Information, a joint service of The Institute of Materials and ASM International. Readers wishing to obtain the full text of articles abstracted here should contact either: The Institute of Materials, 1 Carlton House Terrace, London SWIY 5DB, UK, or: ASM International, Metals Park, OH 44073, USA (not International Journal of Fatigue). The fees charged for photocopying articles are 7.00 for the first ten pages and 3.00 per additional ten pages (UK office), or $10.00 for the first ten pages and $4.00 per additional ten pages (US Office).A differential CDM model for fatigue of unidirectional metal matrix composites. Arnold, S.M. NASA Technical Memorandum TM-105726 1992 22 pp. A multiaxial, isothermal, continuum damage mechanics model for fatigue of a unidirectional metal-matrix composite volume element is presented. The model is phenomenological, stress-based, and assumes a single scalar internal damage variable, the evolution of which is snisotropic. The development of the fatigue damage model (i.e. evolutionary law) is based on the definition of an initially transversely isotropic fatigue limit surface, a static fracture surface and a normalized stress amplitude function. The anisotropy of these surfaces and function, and therefore the model, is defined through physically meaningful invsriants reflecting the local stress and material orientation. This transversely isotropic model is shown, when taken to its isotropic limit, to simplify directly to a previously dsveloped and validated isotropic fatigue continuum damage model. Results of a non-dimensional parametric study illustrate the flexibility of the present formulation in attempting to characterize a class of composite materials and the capability of the formulation in predicting anticipated qualitative trends in the fatigue behaviour of unidirectional metal-matrix composites. Also, specific material parameters representing an initial characterization of the composite system SiC/Ti 15-3 and the matrix material (Ti 15-3) are reported. Graphs, 43 ref. A review of fatigue failures in LWR plants in Japan. lids, K. Nucl. Eng. Des. (Dec. 1992) 138 (3), 297-312 A review is made of fatigue failures of nuclear power plant components in Japan, experienced in service and during periodical inspection. No case has been recently reported of a service fatigue failure of a reactor pressure vessel itself, excluding nozzle corner cracks that occurred many years ago. but service fatigue failures have been experienced occasionally in piping systems, pumps and valves, on which fatigue design seems to have been inadequately applied. The causes of fatigue failures can be divided into two categories: machanicel-vibration-induced fatigue and the rmal-fluctuation-induced fatigue. Vibration-induced fatigue failure occurs more frequently than is generally thought. The lesson gleaned from the present ! survey is a recognition that a service fatigue failure may occur due to any one or a combination of the following factors: (1) lack of communication between designers and fabricetion engineers; (2)lack of knowledge about the possibility of fatigue and inadequate consideration of the effects of residual stresses; (3)lack of consideration of possible vibration in the design and fabrication stages; and (4) lack of fusion or poor penetration in a welded joint. 316L stainless is discussed. Graphs, 5 ref. A feasibility study on the application of localized heating as s life- enhancement technique. Rajic, N. and Wong, A.K. Mech. Mater. (Dec. 1992) 14 (2), 105-125 The possibility of using spot heating to introduce known levels of localized elastic compressive stress in a small region (over a crack tip for example) is investigated. An efficient numerical approach is used to solve the thermal stress problem arising from the application of a concentrated surface heat flux on several axisymmetric bodies, varying from a thin carbon steel plate to a semi-infinite geometry, It is found that a sufficiently large and reversible compressive stress can be generated rapidly in a small region with a relatively low flux energy. This has significant implications in terms of its potential use as a smart fetigue-life enhancement technique. Graphs, 14 ref. Specimen edge effeets on bending fatigue of cedburized steel. Cohen, R.E., Mattock, D.K. and Krauss, G. J. Mater. Eng. Perform. (Oct. 1992) 1 (5), 695-704 The effects of specimen geometry on the fatigue behaviour of SAE 4320 steel csrburized at 927 were evaluated with two sets of cantilever bend specimens, one set machined with square edges and one set machined with round edges. The specimens with square edges exhibited a 13% lower fatigue limit. In comparison with the rounded samples, the lower fatigue limit in the square-edged samples was attributed to the presence of a higher volume fraction of retained austenita in the sample corners and a lower surface residual compressive stress. As a result of the differences in residual stress, preferential crack initiation sites existed in the square- edged samples at a location epprox 200-900 Wn from the square edge. The implications of this study for laboratory analyses of the bending fatigue performance of carburized gear steels are discussed. Graphs,photomicrographs, 22 ref.Calculation for rolling contact fatigue life and strength of cesu-herdened gear materials by computer. Jiang, B, Zheng, X. and Wang, M. ASTMJ. Test. Eval. (Jan. 1993) 21 (1), 9-13 An analysis of the roling contact fatigue process of case-hardened gear material by means of elasticity and fracture mechanics theory has been made; the stress intensity range Ak and equation for crack growth da/dN = c (Ak) was put forward to calculate their fatigue life and strength. The results show that the calculated data are in good agreement with the experimental ones for compound-treated, sprayed, and csrbonitrided specimens. The relative errors of logarithm of cycle number are all 5%. Graphs, 11 ref. Fatigue design, quality control and maintenance of the Ssto Ohashi Bridge. Miki, C. and Okukawa, A. Proc. Conf. Mechanical Behaviour of Materials-VI, Kyoto, Japan, 29 July- 2 Aug. 1991, Vol. 2, pp. 173-180 To examine the influences of weld defects, residual stresses and secondary stresses due to structural details on fatigue strengths, various fatigue tests are carried out under the Honshu-Shikoku Bridge project, which includes 45 and 75 mm thick welded joint specimens, full-scale and large-scale structural models of high-strength steels. Based on these tests, the fatigue design code was established and quality control procedures were incorporated in the fabrication code. Graphs, 8 ref. The influence of prolonged exposure to operating temperatures end strain ageing on the materiel properties of nuclear power plant reactor vessels end pipings. Karzov, G. P., Timofeev, B.T. and Filchagin, Y.G. Int. J. Pressure Vessels and Piping (1993) 53 (2), 195-216 The impact of operating temperature on the mechanical properties of steels and their welded joints in the production of NPP apparatus and pipings used in WER and RBMK reactors is presented. Together with the properties characteristic of types 20, 20K, O8X18H12T and 15 x 2MFA steels after exposure to the temperature range of 250-400 C for 104 h, the values of the mechanical properties of these materials and their weldments (cut from the real components of an operating NPP) after exposure for 105 h at material operating temperatures are given. Variation in properties after such prolonged operation periods is negligible and, moreover, the values of UTS, YS, A and Zare not inferior to those required by the USSR norms of strength calculation. The estimation of structural strength (low-cycle fatigue resistance, and static and cyclic crack resistance) has been carried out as related to pipings manufactured from O8X18H12T steel after their operation period of 105 h. No visible variations of these characteristics have been observed.The influence of strain ageing in the operating temperature range 150-400C on low-cycle fatigue resistance of the 15X2MFA, 15x2HMFA and 22K steels, and their welded joints produced by various welding processes (manual, automatic under flux, electroslag weldings) has also been studied. It has been found that, with the application of specific temperatures and strain rates, the ageing effect may predetermine the material long-term lifetime related to a decrease at the stage of fatigue crack initiation. The strain ageing effect is most evident with low-carbon weld metal after manual arc welding without preheating, which is the welding process that may be applied during assembly. Graphs. 26 ref. Notch effect of welded joints subjected to antipiane shear loading. Radaj, D. and Zhang, S. Eng. Fract. Mech. (Nov. 1992) 43 (4), 663-669 Complementary to existing solutions of the plane problem of notch stress concentration of mild steel welded joints, the antiplane problem is solved using the boundary element method. Typical shape examples of welded joints are considered. Tensile loading is compared with longitudinal shear loading. Based on these solutions, bisxial and oblique loading are dealt with, taking the cruciform joint and transverse stiffener as examples. The fatigue notch factor is determined based on the microstructural support hypothesis proposed by Neuber. Graphs, 8 ref. Sudden burst of the blower impeller. Welding in the World (Nov.-Dec. 1992) 30 (11-12), 294-296 (in English and French) Investigation of the failure of an impeller in an exhaust gas dust extraction system in an LD converter is presented. The impeller design was modified as a result of an examination of the failure, which was found to have been caused by fatigue cracking. Photomicrogra

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