齿轮接触有限元分析外文翻译

变速器论文中英文对照资料外文翻译文献

中英文对照外文翻译 汽车变速器设计 我们知道，汽车发动机在一定的转速下能够达到最好的状态，此时发出的功率比较大，燃油经济性也比较好。因此，我们希望发动机总是在最好的状态下工作。但是，汽车在使用的时候需要有不同的速度，这样就产生了矛盾。这个矛盾要通过变速器来解决。 汽车变速器的作用用一句话概括，就叫做变速变扭，即增速减扭或减速增扭。为什么减速可以增扭，而增速又要减扭呢？设发动机输出的功率不变，功率可以表示为 N = w T，其中w是转动的角速度，T 是扭距。当N固定的时候，w与T是成反比的。所以增速必减扭，减速必增扭。汽车变速器齿轮传动就根据变速变扭的原理，分成各个档位对应不同的传动比，以适应不同的运行状况。 一般的手动变速器内设置输入轴、中间轴和输出轴，又称三轴式，另外还有倒档轴。三轴式是变速器的主体结构，输入轴的转速也就是发动机的转速，输出轴转速则是中间轴与输出轴之间不同齿轮啮合所产生的转速。不同的齿轮啮合就有不同的传动比，也就有了不同的转速。例如郑州日产ZN6481W2G型SUV车手动变速器，它的传动比分别是：1档3.704:１；2档2.202:1；3档1.414:1；4档1:1；5档（超速档）0.802:1。 当汽车启动司机选择1档时，拨叉将1/2档同步器向后接合1档

齿轮并将它锁定输出轴上，动力经输入轴、中间轴和输出轴上的1档齿轮，1档齿轮带动输出轴，输出轴将动力传递到传动轴上（红色箭头）。典型1档变速齿轮传动比是3:1,也就是说输入轴转3圈，输出轴转1圈。 当汽车增速司机选择2档时，拨叉将1/2档同步器与1档分离后接合2档齿轮并锁定输出轴上，动力传递路线相似，所不同的是输出轴上的1档齿轮换成2档齿轮带动输出轴。典型2档变速齿轮传动比是2.2:1，输入轴转2.2圈，输出轴转1圈，比1档转速增加，扭矩降低。 当汽车加油增速司机选择3档时，拨叉使1/2档同步器回到空档位置，又使3/4档同步器移动直至将3档齿轮锁定在输出轴上，使动力可以从轴入轴—中间轴—输出轴上的3档变速齿轮，通过3档变速齿轮带动输出轴。典型3档传动比是1.7:1，输入轴转1.7圈，输出轴转1圈，是进一步的增速。 当汽车加油增速司机选择4档时，拨叉将3/4档同步器脱离3档齿轮直接与输入轴主动齿轮接合，动力直接从输入轴传递到输出轴，此时传动比1:1，即输出轴与输入轴转速一样。由于动力不经中间轴，又称直接档，该档传动比的传动效率最高。汽车多数运行时间都用直接档以达到最好的燃油经济性。 换档时要先进入空档，变速器处于空档时变速齿轮没有锁定在输出轴上，它们不能带动输出轴转动，没有动力输出。 一般汽车手动变速器传动比主要分上述1－4档，通常设计者首先确定最低（1档）与最高（4档）传动比后，中间各档传动比一

基于有限元分析的发动机缸体压铸模具设计【毕业论文(含任务书、外文翻译)】

BI YE SHE JI （20 届） 基于有限元分析的发动机缸体压铸模具设计 所在学院 专业班级材料成型与控制工程 学生姓名学号 指导教师职称 完成日期年月

任务下达日期：2016年3月1日 毕业设计日期：2016年3月1日至2016年6月12日 毕业设计题目：基于有限元分析的发动机缸体压铸模具设计 毕业设计主要内容和要求： 内容： 1、查阅30篇中文文献及10篇左右的英文文献，充分了解设计内容。 2、利用NX10.0建立缸体三维模型，使用Anycasting完成缸体压铸过程模拟分析。 3、参考设计手册和模拟结果完成压铸模具设计，并绘制模具工程图。 4、要求翻译一篇近三年的英文文献，汉字内容应不少于3000字。 要求： 1、努力学习、勤于实践、勇于创新，保质保量地完成毕业设计任务。 2、遵守纪律，保证出勤。因事、因病离岗，应事先向指导老师请假。否则作为缺席处理。 3、独立完成规定的工作内容。不弄虚作假，不抄袭和拷贝别人的工作内容。 4、毕业设计必须符合中国矿业大学毕业论文规范化规定，否则不得参加毕业答辩。 院长签字：指导教师签字：

本文以某汽车的发动机铝合金缸体压铸件为研究对象，对该缸体压铸件可能铸造缺陷进行分析及预测。首先利用NX10.0设计该缸体的三维模型，并参照设计手册完成浇注系统和排溢系统的设计。然后利用铸造模拟软件anycasting v4.0对压铸模具型腔、浇注系统和排溢系统整体进行充填和凝固过程进行模拟研究。分析目前的工艺和设计的浇注系统、排溢系统的是否存在问题，对重要的压铸工艺参数进行优化，并优化压铸模具浇注系统和排溢系统。根据以上模拟结果和设计手册，利用NX10.0、AUTOCAD完成其余结构的设计。使用anycasting v4.0主要完成充型分析，充型过程热分析和热凝固分析，其中重要的工艺参数是冲头快压射速度、浇注温度、冲头高低速转换点和模具预热温度，最后得到一个缺陷比较少的模拟结果。对一般充型缺陷，可以通过优化设计浇注系统、排气系统改进，对凝固缺陷可以通过修改冷却系统的位置进行改进。模具设计部分包括模具型芯部分设计、模架设计、侧抽芯系统设计、顶出系统设计、模具厚度核算、动模座板行程校核、最小合模距离与最大开模距离校核和模具最大外形轮廓校核。最后依据模拟分析结果和模具结构设计，利用NX10.0三维造型软件完成缸体铸件的压铸模具设计。 关键词：铝合金缸体、数值模拟、压铸、模具设计

外文翻译-齿轮机构

翻译部分 英文原文 Gear mechanisms Gear mechanisms are used for transmitting motion and power from one shaft to another by means of the positive contact of successively engaging teeth. In about 2,600B.C., Chinese are known to have used a chariot incorporating a complex series of gears like those illustrated in Fig.2.7. Aristotle, in the fourth century B .C .wrote of gears as if they were commonplace. In the fifteenth century A.D., Leonardo da Vinci designed a multitude of devices incorporating many kinds of gears. In comparison with belt and chain drives ,gear drives are more compact ,can operate at high speeds, and can be used where precise timing is desired. The transmission efficiency of gears is as high as 98 percent. On the other hand, gears are usually more costly and require more attention to lubrication, cleanliness, shaft alignment, etc., and usually operate in a closed case with provision for proper lubrication. Gear mechanisms can be divided into planar gear mechanisms and spatial gear mechanisms. Planar gear mechanisms are used to transmit motion and spatial gear mechanisms. Planar gear mechanisms are used to transmit motion and power between parallel shafts ,and spatial gear mechanisms between nonparallel shafts. Types of gears (1)Spur gears. The spur gear has a cylindrical pitch surface and has straight teeth parallel to its axis as shown in Fig. 2.8. They are used to transmit motion and power between parallel shafts. The tooth surfaces of spur gears contact on a straight line parallel to the axes of gears. This implies that tooth profiles go into and out of contact along the whole facewidth at the same time. This will therefore result in the sudden loading and sudden unloading on teeth as profiles go into and out of contact. As aresult, vibration and noise are produced. (2)Helical gears. These gears have their tooth elements at an angle or helix to the axis of the gear(Fig.2.9). The tooth surfaces of two engaging helical gears inn planar gear mechanisms contact on a straight line inclined to the axes of the gears. The length of the contact line changes gradually from zero to maximum and then from maximum to zero. The loading and unloading of the teeth become gradual and smooth. Helical gears may be used to transmit motion and power between parallel shafts[Fig. 2.9(a)]or shafts at an angle to each other[Fig. 2.9(d)]. A herringbone gear [Fig. 2.9(c)] is equivalent to a right-hand and a left-hand helical gear placed side by side. Because

齿轮接触强度与弯曲强度

1. 齿轮接触强度计算 1.1齿轮接触的计算应力 βανεννπσK K K K u u bd F Z Z Z MPa E E R L F H A t E H red H 1)(11112 2 2121±?=-+-= 式中： A K —工况系数； νK —动载系数； αH K —接触强度的端面载荷分配系数； βK —齿向载荷分布系数； H Z —节点域系数； E Z —弹性系数； εZ 一重合度系数； 1.1.1 工况系数A K 由于齿轮的载荷特性为工作稳定状况下，故取工况系数为A K =1.0. 1.1.2 动载系数νK 由于 =15.96m/s 齿轮重合度 再根据《机械设计手册》图8-32与8.33得；

)=1.48-0.44(1.48-1.22)=1.36 1.1.3 端面载荷分配系数αH K 查表8-120得 21εαZ C K H H ? = 其中H C 查图8-34为0.865. 1.1.4 齿向载荷分布系数βK 查图8.35可得βK =1.13. 1.1.5 节点域系数H Z 式中：错误！未找到引用源。为端面分度圆压力角； 错误！未找到引用源。 为基圆螺旋角； 错误！未找到引用源。 为端面啮合角； 经计算最后得到H Z =2.254 1.1.6 弹性系数E Z 带入各值后，得E Z =189.87错误！未找到引用源。。 1.1.7 重合度系数εZ 与1.13的分母约去，不需考虑。

最后得到理论接触应力为： MPa Z mm mm N Z MPa H 67.124413 .11 865.036.11208.2208.3776.1572.7627.5265287.189254.2=???????? ??=ε εσ 1.2 接触疲劳极限lim H σ' W R V L N H H Z Z Z Z Z lim lim σσ=' 式中： 'H l i m σ表示计算齿轮的接触疲劳极限； Hlim σ表示试验齿轮的接触疲劳极限； N Z 表示接触强度的寿命系数； L Z 表示润滑剂系数； V Z 表示速度系数； R Z 表示光洁度系数； W Z 表示工作硬化系数。 1.2.1 试验齿轮的接触疲劳极限lim 1H σ 由手册中图8-38d 查得lim 2lim 1H H σσ==1690MPa 。 1.2.2 接触强度的寿命系数N Z 查表8-123得6 0102?=N ， nt N e γ60= 0N N e >，取121==N N Z Z 。 1.2.3 润滑剂系数L Z 取10050=υ，由图8-40查得21L L Z Z ==1. 1.2.4 速度系数V Z 由图8-41，按V=1米/秒和MPa H 1200lim >σ查得95.021==V V Z Z 。

渐开线直齿圆柱齿轮接触应力有限元分析

渐开线直齿圆柱齿轮接触应力有限元分析 摘要：本文针对ANSYS有限元齿轮接触仿真进行了探讨，计算齿轮的等效应力和接触应力，对齿轮的弯曲强度失效和接触疲劳失效研究具有重要的实际意义。利用有限元分析方法，得出了相互啮合齿轮在静态情况下，等效应力和接触应力的分布规律；同时分析了齿轮与不同直径齿轮接触时，等效应力和接触应力的变化情况。 关键词：齿轮接触有限元等效应力接触应力 ANSYS 引言 齿轮的接触问题是典型的接触非线性问题，在传统的计算设计方法中，我们通常将非线性问题进行一定的简化与假设，使之变为线性问题来求解，但是这种计算方法的结果不是十分精确。本文基于ANSYS软件建立渐开线直齿圆柱齿轮的二维有限元模型，对静载荷作用下齿轮接触问题进行有限元分析，求得齿轮接触问题更为精确的解，为解决齿轮接触问题提供了一定依据。 1 齿轮传动失效分析 齿轮传动的失效主要是轮齿的失效。根据齿轮传动工作和使用条件的不同，齿轮传动也就有不同的失效形式。主要的失效形式有轮齿的折断、齿面疲劳点蚀、磨损、胶合和塑性变形等。设计齿轮传动时，应对具体情况作具体分析，按可能发生的主要损伤或失效形式来进行相应的强度计算，有时以齿根弯曲疲劳强度为主，有时以齿面接触疲劳为主。这些问题采用有限元法来计算是十分方便的，下面我们将通过ansys对传动比不同的3组齿轮进行有限元分析。 2 有限元模型及其求解 2.1模型的建立 齿轮均选用标准渐开线直齿圆柱齿轮，模数m=3，压力角α=20°，齿数分别为Z1=35、Z2=25、Z3=20，传动比分别为35:35、25:35、20:35。在建模时考虑到齿轮具有轴对称结构，每个齿的受力情况基本相同，因此可以将齿轮模型简化为平面问题，这样可以节省大量计算时间。先在三维设计软件Pro/E中生成齿轮的三维模型，再将模型保存为iges格式，然后导入到ansys中，删除多余面，仅剩下齿轮端面，并复制一个齿轮并调整角度，可得如图1所示的齿轮实体模型。

有限元分析系统的发展现状与展望外文翻译

Finite element analysis system development present situation and forecast Along with modern science and technology development, the people unceasingly are making the faster transportation vehicle, the large-scale building, the greater span bridge, the high efficiency power set and the preciser mechanical device. All these request engineer to be able precisely to forecast in the design stage the product and the project technical performance, needs to be static, technical parameter and so on dynamic strength to the structure as well as temperature field, flow field, electromagnetic field and transfusion carries on the analysis computation. For example analysis computation high-rise construction and great span bridge when earthquake receives the influence, has a look whether can have the destructive accident; The analysis calculates the nuclear reactor the temperature field, the determination heat transfer and the cooling system are whether reasonable; Analyzes in the new leaf blade the hydrodynamics parameter, enhances its operating efficiency. The sell may sum up as the solution physics question control partial differential equations often is not impossible. In recent years the finite element analysis which develops in the computer technology and under the numerical analysis method support(FEA, Finite Element Analysis) the side principle for solves these complex project analysis estimation problems to provide the effective way. Our country in " 95 " Plan period vigorously promotes the CAD technology, mechanical profession large and middle scalene terries CAD popular rate from " 85 " End 20% enhances that present 70%.With enterprise application of CAD, engineering and technical personnel has gradually get rid drawing board, and will join the main energy how to optimize the design, engineering and improving the quality of products, computer-aided engineering analysis (CAE. Computer Aided Engineering) method and software will be the key technical elements . ln engineering practice, finite element analysis software and CAD system integration design standards should be a qualitative leap, mainly in the following aspects : The increase design function, reduces the design cost; Reduces design and the analysis cycle period; Increase product and project reliability; Uses the optimized design, reduces the material the consumption or the cost;

轴和齿轮的设计及应用外文翻译、中英文翻译、外文文献翻译

英文原文： SHAFT AND GEAR DESIGN Abstract: The important position of the wheel gear and shaft can' t falter in traditional machine and modern machines. The wheel gear and shafts mainly install the direction that delivers the dint at the principal axis box. The passing to process to make them can is divided into many model numbers, useding for many situations respectively. So we must be the multilayers to the understanding of the wheel gear and shaft in many ways Key words : Wheel gear ; Shaft In the force analysis of spur gears, the forces are assumed to act in a single plane .We shall study gears in which the forces have three dimensions.The reason for this, in the case of helical gears, is that the teeth are not parallel to the axis of rotation. And in the case of bevel gears, the rotational axes are not parallel to each other. There are also other reasons, as we shall learn.Helical gears are used to transmit motion between parallel shafts. The helix angle is the same on each gear, but one gear must have a right-hand helix and the other a left-hand helix. The shape of the tooth is an involute helicoid. If a piece of paper cut in the shape of a parallelogram is wrapped around a cylinder, the angular edge of the paper becomes a helix. If we unwind this paper, each point on the angular edge generates an involute curve. The surface obtained when every point on the edge generates an involute is called an involute helicoid. The initial contact of spur-gear teeth is a line extending all the way across the face of the tooth. The initial contact of helical gear teeth is a point, which changes into a line as the teeth come into more engagement. In spur gears the line of contact is parallel to the axis of the rotation; in helical gears, the line is diagonal across the face of the tooth. It is this gradual of the teeth and the smooth transfer of load from one tooth to another, which give helical gears the ability to transmit heavy loads at high speeds. Helical gears subject the shaft bearings to both radial and thrust loads. When the thrust loads become high or are objectionable for other reasons, it may be desirable to use double helical gears. A double helical gear (herringbone) is equivalent to two helical gears of opposite hand, mounted side byside on the same shaft. They develop opposite thrust reactions and thus cancel out the thrust load. When two or more single helical gears are mounted on the same shaft,the hand of the gears should be selected so as to produce the minimum thrust load Crossed-helical, or spiral, gears are those in which the shaft centerlines are neither parallel nor intersecting. The teeth of crossed-helical fears have point contact with each other, which changes to line contact as the gears wear in. For this reason they will carry out very small loads and are mainly for instrumental applications, and are definitely not recommended for use in the transmission of power There is on difference between a crossed heli cal gear and a helical gear until they are mounted in mesh with each other. They are manufactured in the same way. A pair of meshed crossed helical gears usually have the same hand; that is , a right-hand driver goes with a right-hand driven. In the design of crossed-helical gears, the minimum sliding velocity is obtained when the helix angle are equal. However, when the helix angle are not equal, the gear with the larger helix angle should be used as the driver if both gears have the same hand Worm gears are similar to crossed helical gears. The pinion or worm has a small number of teeth, usually one to four, and since they completely wrap around the pitch cylinder they are called threads. Its mating gear is called a worm gear, which is not a true helical gear. A worm and worm

外文翻译：轿车车身的碰撞有限元模型分析

附录1 汽车的碰撞安全性越来越得到人们的重视,不论是对轿车、小客车或其它类型的车辆。由于进行碰撞试验往往需要许多时间与金钱,计算机仿真就是一条较好的方法。而且,汽车被动安全性研究的有限元方法的发展,非线性动力显式有限元方法的进步,使得利用计算机仿真来进行汽车安全性评价与改进成为可能。目前,各大汽车公司与研究机构已着手研究从仿真分析的结果中推演出进一步的修改方案,达到在汽车重量与碰撞特性等方面最优的研究。本文以提高汽车耐撞性为目标,以某型七座小客车的初步设计方案为基础,建立了用于正面碰撞仿真的前部碰撞有限元模型,并进行了计算机碰撞模拟,提出了改进方案,提高了汽车的被动安全性设计水平,从而提高了新车型满足碰撞全法规的成功率。 在对汽车进行碰撞性能有限元分析时,汽车整车的建模工作量巨大。本文中的整车有限元模型中的各个零件均由各零件的U G或CATIA 格式的几何模型转入HYPERME2SH 有限元建模软件并进行网格划分,再进行装配而成。碰撞分析的有限元模型的节点数和单元数都超过了14 万,规模较大。有限元分析软件采用LS2DYNA ,它是当前在汽车碰撞有限元仿真中应用较多的一个非线性动力显式有限元软件,它的主要算法采用Lagrangian 描述增量法,利用显示中心差分法离散时间域,积分时间步长大小受Courant 稳定性准则制约。 整车结构由100 多个元件装配而成。建模时,连接的刚度和强度根据实际情况确定。模型中的板壳单元以Be2lytschko - Tsay 四边形壳单元为主。而节点也分为常规节点和模拟部分焊点情况的带失效的固连。发动机和变速器在整车碰撞中的变形不予以考虑,其材料定义为刚性材料。车门和车体的连接是通过铰链和门锁固定的,在数值仿真中,通过约束对应节点的位移自由度建立球铰模型来模拟。 考虑到研究中仿真的碰撞方式是最为典型的正面碰撞,在正面碰撞过程中,A 柱前部的车身结构是变形吸能的主要器件,其变形的模式极为复杂,而中柱之后在碰撞过程中几乎不发生变形。为节省计算时间,将车身的前部单元划分较密,中柱之后则较稀。计算中采用弹性刚度沙漏控制。 按照CMVDR294 碰撞法规的要求,小客车以50km/ h的速度正面撞击刚性墙。设置的初始边界条件与实车实验的初始条件相同,模拟该车以50km/ h 的初速度正面撞击刚体墙。在有限元计算后进行后处理,并对模拟计算的结果进

abaqus 有限元分析(齿轮轴)

Abaqus分析报告 （齿轮轴） 名称：Abaqus齿轮轴 姓名： 班级： 学号： 指导教师：

一、简介 所分析齿轮轴来自一种齿轮泵，通过用abaqus软件对齿轮轴进行有限元分析和优化。齿轮轴装配结构图如图1，分析图1中较长的齿轮轴。 图1.齿轮轴装配结构图 二、模型建立与分析 通过part、property、Assembly、step、Load、Mesh、Job等步骤建立齿轮轴模型，并对其进行分析。 1.part 针对该齿轮轴，拟定使用可变型的3D实体单元，挤压成型方式。 2.材料属性 材料为钢材，弹性模量210Gpa，泊松比0.3。

3.截面属性 截面类型定义为solid，homogeneous。 4.组装 组装时选择dependent方式。 5.建立分析步 本例用通用分析中的静态通用分析（Static，General）。 6.施加边界条件与载荷 对于齿轮轴，因为采用静力学分析，考虑到前端盖、轴套约束，而且根据理论，对受力部分和轴径突变的部分进行重点分析。 边界条件：分别在三个轴径突变处采用固定约束，如图2。 载荷：在Abaqus中约束类型为pressure，载荷类型为均布载荷,分别施加到齿轮接触面和键槽面，根据实际平衡情况，两力所产生的绕轴线的力矩方向相反，大小按比例分配。 均布载荷比计算： 矩形键槽数据： 长度：8mm、宽度：5mm、高度：3mm、键槽所在轴半径：7mm 键槽压力面积：S1 = 8x3=24mm2 平均受力半径：R1=6.5mm 齿轮数据：= 齿轮分度圆半径：R2 =14.7mm、压力角：20°、 单个齿轮受力面积：S2 ≈72mm2 通过理论计算分析，S1xR1xP1=S2xR2xP2，其中，P1为键槽均布载荷

外文翻译--齿轮和齿轮传动

Gears and gear drive Gears 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

机械毕业设计英文外文翻译64超高速行星齿轮组合中内部齿轮的有限元分析

翻译部分 英文原文 Finite Element Analysis of internal Gear in High-Speed Planetary Gear Units Abstrac t: The stress and the elastic deflection of internal ring gear in high-speed spur planetary gear units are investigated. A rim thickness parameter is defined as the flexibility of internal ring gear and the gearcase. The finite element model of the whole internal ring gear is established by means of Pro/E and ANSYS. The loads on meshing teeth of internal ring gear are applied according to the contact ratio and the load-sharing coefficient. With the finite element analysis(FEA),the influences of flexibility and fitting status on the stress and elastic deflection of internal ring gear are predicted. The simulation reveals that the principal stress and deflection increase with the decrease of rim thickness of internal ring gear. Moreover, larger spring stiffness helps to reduce the stress and deflection of internal ring gear. Therefore, the flexibility of internal ring gear must be considered during the design of high-speed planetary gear transmissions. Keywords: planetary gear transmissions; internal ring gear; finite element method High-speed planetary gear transmissions are widely used in aerospace and automotive engineering due to the advantages of large reduction ratio, high load capacity, compactness and stability. Great attention has been paid to the dynamic prediction of gear units for the purpose of vibration reduction and noise control in the past decades(1-8).as one of the key parts, internal gear must be designed carefully since its flexibility has a strong influence on the gear train’s performance. studies have shown that the flexibility of internal gear significantly affects the dynamic behaviors of planetary gear trains(9).in order to get stresses and deflections of ring gear, several finite element analysis models were proposed(10-14).however, most of the models dealt with only a segment of the internal ring gear with a thin rim. the gear segment was constrained with corresponding boundary conditions and appoint load was exerted on a single tooth along the line of action without considering the changeover between the single and double contact zone in a complete mesh cycle of a given tooth. A finite element/semi-analytical nonlinear contract model was presented to investigate the effect of internal gear flexibility on the quasi-static behavior of a planetary gear set(15). By considering the deflections of all gears and support conditions of splines, the stresses and deflections were quantified as a function of rim thickness. Compared with the previous work, this model considered the whole transmission system. However, the method described in Ref. (15) requires a high level of expertise before it can even be successful. The purpose of this paper is to investigate the effects of rim thickness and support conditions on the stress and the deflection of internal gear in a high-speed spur planetary gear transmission. Firstly, a finite element model for a complete internal gear fixed to gearcase with straight splines is created by means of Pro/E and ANSYS. Then, proper boundary conditions are applied to simulating the actual support conditions. Meanwhile the contact ratio and load sharing are considered to apply suitable loads on meshing teeth. Finally, with the commercial finite element code of APDL in ANSYS, the influences of rim thickness and support condition on