基于有限元法，旋耕机传动齿轮应力分析·穆罕默德托帕克库萨特西里克丹妮资耶尔马兹易卜拉欣阿辛琪阿克登尼基大学农学院，安塔利亚，土耳其农业机械部2008年8月12日摘要旋耕机的耕作工具，获取自己的运动由拖拉机动力起飞（PTO）有被设计为混合土。
降低土壤交通在很大程度上与此工具混合土。
使用旋耕机是提高我国由于其许多优点。
旋耕机结构具有一个齿轮箱，改变运动方向由拖拉机动力输出轴90度，旋转速度传动齿轮和转子轴放置在水平的土壤混合。
有刀片在进入转子轴件和混合土。
特别是，在刀片和传动齿轮，变形发生由于高无振动，高功率，土壤的部分影响，使用条件设计制造误差和错误。
特别是用于建筑和传动部件的应力分布，为理解好的确定失败的原因。
在这项研究中，传动的旋耕机而设计制造的一种本地制造商被建模为三维参数化设计软件和结构应力在根据其工作使用有限元软件模拟了在传动齿轮的分布条件。
后仿真结果评价，对齿轮应力分布表明，齿轮工作无故障根据齿轮的材料应力屈服。
此外，计算的参考齿轮工作安全系数仿真结果。
关键词：旋耕机，应力分析，有限元法1.引言旋耕机耕作机，适用于农田、果园，在农业。
旋耕机有削减巨大的能力，混合土和苗床准备直接制备。
此外，旋耕机有更多的混合能力是比犁的七倍。
旋耕机是连接到拖拉机三点联动系统，它是由拖拉机动力输出轴驱动（PTO）。
运动的方向改变90度，从拖拉机动力输出第二齿轮箱的水平轴。
转子轴与第二齿轮箱的运动。
旋耕机的元素在其他作用力下由于高无振动，高功率，土壤的部分影响，设计制造错误和错误的使用条件，耕作。
因此，不需要的应力在它的元素分布。
如果元素不能补偿的操纵力，这些元素变得毫无用处，因为打破或大变形破坏。
特别是叶片及传动元件必须耐用于操纵力下。
应力分布的预测是非常重要的无故障产生的良好工作的设计和产品设计师和制造商。
机的厂家，要为自己的机器，可能的错误，防止使用的材料，具有很高的安全系数，或者他们使用高质量的机械元件。
虽然这些措施可以安全，产品的重量和成本的上升。
帮助开发的技术和设计软件，集成在新的代计算机，设计变得更加方便和可靠的。
设计师可以设计在虚拟屏幕上自己的产品和他们可以利用计算机仿真技术，评价产品的工作条件。
今天的三维（3D）与有限元法的应用中越来越广泛的建模工业。
许多三维建模和有限元的应用实例可以在不同的工程学科（谷内，见1993）。
在这项研究中，一种旋耕机传动齿轮火车，这是由本地制造商制造，采用Solid Works三维参数化建模设计软件。
三维建模后的程序，进行了模拟研究在利用COSMOS Works有限元软件传动齿轮火车。
旋耕机和第二齿轮箱传动轮系及其三维模型在图1中给出的。
此外，图2显示了一个架构，是属于旋耕机传动系统（不同等人。
，2005）。
如下图所示架构的运动和动力的传递与拖拉机动力输出万向节连接到第一齿轮箱有2个螺旋锥齿轮的齿数的10和23，然后到第二齿轮箱轴。
2。
材料和方法2.1三维建模及应力分析传动齿轮根据齿轮传动齿轮的原尺寸模型，然后他们聚集。
通过图3可以看到他们的3D 模型和它的值在表1中给出的。
开始的应力分析，我们认为，在正常工作条件下工作的齿轮。
在耕作，与旋耕机的操作，所需的拖拉机动力输出功率为49.5千瓦拖拉机动力输出革命是540分钟，根据拖拉机动力输出功率和传动比的齿轮，时刻齿轮已经占用。
表1。
传动齿轮的值在模拟中，两种分析各齿轮副齿轮产生（I-II和齿轮II-III）对工作条件。
分析了已生成的三维，静态和线性COSMOS Works有限元软件的假设。
各向同性材料属性中使用的齿轮材料的模拟和性能的了表2（库塔，2003）。
装配时，值得注意的是，在接触工作齿轮的齿，配对就在彼此接触条件下的单。
因为，实验结果表明，对齿轮的表面发生的最大应力和失效对齿轮接触区和齿根单接触条件（库股，1993）。
表2。
齿轮的材料特性2.2齿轮1和齿轮II之间的应力分析齿轮和齿轮II我组装后，施加边界条件。
齿轮II固定于其轴轴承。
占矩值法旋转轴方向的网格构造齿轮我在图4中可以看到。
COSMOS Works啮合的功能已被用于地图网格。
高阶（二级）的抛物型固体四面体单元具有四个角节点，六中间节点，六边的高质量的网格划分功能（COSMOS 工程建设，2006）。
在啮合操作，共342160个元素和获得489339个节点的包含，总共对于啮合的齿轮1和齿轮II来说。
在求解过程中，应力分布如图5所示的了，对齿轮和齿轮II。
作为一个结果的最大等效应力（von米塞斯），确定对齿轮工作齿的接触面为我和123.59 MPa，73.98 MPa时最大等效应力由齿轮工作齿II确定。
2.3齿轮II和齿轮III的应力分析在这一部分中，同样的必要程序，应用应力分析齿轮II和齿轮 III施加边界条件，生成的网格划分和求解程序。
齿轮III被固定在轴承和占力矩值应用于齿轮II。
在啮合操作模型，总共有326600个元素468512总节点啮合齿轮II和III总齿轮（图6）。
结果图显示对齿轮II和III在图7齿轮。
分析结果表明，最大等效应力发生在接触表面加工齿轮III为47.13 M Pa。
根据施加的力矩46.37 M Pa的等效应力值对齿轮II齿面接触区发生工作。
得到的仿真结果表明，我们是如何工作的分布应力传动齿轮齿。
根据仿真结果和齿轮材料的屈服应力，工作安全系数占传动齿轮（表3）。
表3。
传动齿轮的工作安全系数参考文献耶尔马兹，博士，卡纳克基先生，2005。
一种旋耕机齿轮失效。
工程失效分析，12（3）：400～404。
2006软件COSMOS Works帮助文件，2006。
COSMOS Works用户指南。
库股，1993。
机械元件。
科贾埃利大学出版社，第二卷，科贾埃利（土耳其）。
库塔，M.G.，2003。
指导制造商。
比尔深出版社，伊斯坦布尔（土耳其）。
谷内，D.，1993。
有限元原理方法工程师。
（翻译），萨卡里亚大学出版社，No.03，萨卡里亚（土耳其）。
奥美资，A.，2001。
园林植物的机械化。
阿克登尼基大学出版社：No.76，安塔利亚，（土耳其）。
STRESS ANALYSIS ON TRANSMISSION GEARS OF A ROTARY TILLER USING FINITE ELEMENT METHOD Mehmet TOPAKCI a H.Kursat CELIK Deniz YILMAZ Ibrahim AKINCI Akdeniz University, Faculty of Agriculture, Department of Agricultural Machinery,Antalya, TurkeyAccepted 12 August 2008Abstract:Rotary tiller is one of the tillage tools which gets own motion from tractor power take off (PTO) and it had been designed for blend to soil. Soil traffic is decreased to great extent with this tool by blending the soil. Using of rotary tiller is increasing nowadays in our country because of its many benefits. Rotary tiller construction has a gear box that changes motion direction with 90 degrees from tractor PTO, transmission gears for rotation velocity and a rotor shaft which placed as horizontal to soil for blending. There are cutter blades on rotor shaft for breaking into pieces and blend to soil. Especially, on cutter blade and transmission gears, deformations occur because of high vibration, pointless high power, impact effect of soil parts, design-manufacturing error and wrong using conditions. Especially for construction and transmission parts, stress distributions should be determined well for understand failure reasons. In this study, transmission gear train of a rotary tiller which was designed and manufactured by a local manufacturer was modeled as three-dimensional in a parametric design software and structural stress distributions on transmission gears were simulated using a finite element method software according to its operating condition. After evaluating of simulation results, stress distributions on gears show that gears working without failure according to yield stress of gear’s materials. Additionally, working safety coefficient of gears calculated by reference simulation results.Keywords: Rotary Tiller, Stress Analysis, Finite Elements Method1. IntroductionRotary tiller is a tillage machine which is used in arable field and fruit gardening agriculture. Rotary tiller has a huge capacity for cutting, mixing to topsoil and preparing the seedbed preparation directly. Additionally, a rotary tiller has more mixing capacity seven times than a plough ( Ozmerzi , 2002).The rotary tiller is attached to three point linkage system of a tractor and it is driven by the tractor PTO (Power Take Off). The motion direction is changed as 90 degrees from tractor PTO to second gear box by horizontal shaft. The rotor shaft gets its motion from second gear box.Rotary tiller’s elements work under miscellaneous forces because of high vibration, pointless high power, impact effect of soil parts, design-manufacturing errors and wrong using conditions in tillage operation. Therefore, undesired stress distributions occur on its elements. If the elements cannot compensate to the operating forces, these elements become useless because of breaking or high deformation failure. Especially blades and transmission elements have to be durable against to operating forces. Predicting to stress distributions is so important for the designers and manufacturers to generate good working designs and products without failure. Machine manufacturers, which want to prevent for probable errorsof their own machines, use materials, which have high safety coefficient, or they use high weight machine elements. Although these prevention methods can be safety, weight and cost of products rise.Helping with developed technologies and design software which integrated in new generation computers, designs are getting easier and reliable. Designers can design own products in virtual screen and they can evaluate working condition of the products by simulating techniques using the computers. Today three-dimensional (3D) modeling and finite elements method applications are getting so widespread in the industry. Many of 3D modeling and finite elements application samples can be seen on different engineering disciplines (Gunay, 1993).In this study, transmission gear train of a rotary tiller, which was designed and manufactured by a local manufacturer, was modeled using Solid works 3D parametric design software. After 3D modeling procedure, a simulation study was carried out on the transmission gear train using Cosmos works finite elements software. Rotary tiller and its second gear box transmission gear train and its 3D model were given in Figure 1. Additionally, Figure 2 shows a schema that is belong to transmission system of rotary tiller (Akinci et al., 2005). As shown in the schema that motion and power transmit with universal joint from tractor PTO output to first gear box that has 2 helical bevel gears which have 10 and 23 number of teeth and then goes to second gear box to rotor shaft.2. Materials and Methods2.1 3D Modeling and Stress Analysis ofTransmission GearsTransmission gears were modeled according to original dimensions of gears then they were assembled. It can be seen in Figure 3 their 3D model and its values were given in Table 1. Getting started stress analysis, we assumed that gears are working in normal working condition. In the tillageoperation with rotary tiller, required tractor PTO power was taken as 49.5 kWand tractor PTO revolution was 540 min According to tractor PTO power and transmission ratios, moments of gears have been accounted.In simulation, two analyses generated for each two gear pairs (Gear I-II and Gear II-III) on working condition. Analyses have been generated in3D, static and linear assumptions in Cosmos works finite elements software. Isotropic material properties were used in simulation and properties of gear’s material was given at Table 2 (Kutay, 2003). While assembling, it was noted that working gear’s tooth in contact, pairedjust at single contact condition with each others. Because, experiments show that maximum stresses and failures on gears occur on gear’s surface contact zone and tooth root on single contact condition (Curgul, 1993).2.2 Stress Analysis Between on Gear I and Gear IIAfter assembling of Gear I and Gear II, boundary condition was applied. Gear II fixed from bearing of its shaft. Accounted moment value was applied at direction of rotation axis to Gear I and its mesh construction can be seen in Figure 4.Cosmos works meshing functions have been used to map the meshing. Higher-order (Second-order) parabolic solid tetrahedral element which has four corner nodes, six mid-side nodes, and six edges attached by meshing function for high quality mesh construction (Cosmos Works, 2006).After meshing operation, 342160 total elements and 489339 total nodes obtained for meshed Gear I and Gear II in total.After solve process, stress distributions has been shown in Figure 5 for pairs of Gear I and Gear II. As a result maximum equivalent stress (Von Mises) determined on the contact surface of working teeth of Gear I as 123.59 M Pa and 73.98 M Pa maximum equivalent stresses determined on working teeth of Gear II.2.3 Stress Analysis Between on Gear II andGear IIIIn this section, same necessary procedures are applied for stress analysis of Gear II and Gear III. Boundary conditions are applied, generated meshing and solve procedure. Gear III has been fixed on bearing and accounted moment value is applied to Gear II. After meshing operation models have 326600 total elements and 468512 total nodes for meshed Gear II and Gear III in total (Figure 6).Result plots were showed for pairs of Gear II and Gear III in Figure 7. Analysis results show that maximum equivalent stress occurred on contact surface working teeth of Gear III as 47.13 M Pa. According to applied moment 46.37 M Pa equivalent stress value occurred on contact zone of working teeth of Gear II.Obtained simulation results show us to how is distributing stresses on working teeth of transmission gears. According to simulation results and yield stress of gear’smaterial, working safety coefficient accounted for transmission gears (Table 3).3. ConclusionsIn this study, stress distributions were simulated on transmission gears of a rotary tiller which designed and manufactured by local manufacturer. For this aim, transmission gears were modeled and structural stress analysis was generated using Solid works 3D parametric software and Cosmos works finite elements software. According to simulation results, following notes can be said;1. When transmission gears were evaluated in the simulation results according to yield stress of gear’s material, no failur e was detected on gears. Gears are working on normal condition.2. In stress analysis between Gear I and Gear II, maximum equivalent stress was determined on contact surface of working teeth of Gear I as 123.59 M Pa. In same results plot of Gear II working teeth has 73.98 M Pa stress value on contact surface.3. In stress analysis between Gear II and Gear III, maximum equivalent stress was determined on contact surface of working teeth of Gear III as 47.13 M Pa. Maximum stress value was determined 46.37 M Pa on working teeth of Gear II contact surface.4. According to simulation maximum stress results on gears, working safety coefficients are accounted for Gear I, Gear II and Gear III as shown Table 3.To use materials which have high safety coefficients are looking easy and well applications for designers. But this way goes excessive cost rising, weight and time. Avoid for these results, using of simulation techniques and pc-software which are prepared for designers, are so useful tools and applications to gain time and manufacturing costs. In addition, it is possible to increase the quality and capacity of optimum machinery and tool design in agricultural mechanization systems.ReferencesAkinci. I, Yilmaz, D., Çanakci, M., 2005. Failure of a Rotary Tiller Spur Gear. Engineering failure analysis, 12(3): 400- 404.Cosmos Works 2006 software help file, 2006. Cosmos Works user guide.Curgul, İ., 1993. Machine Elements. University of Kocael i press ,Volume II, Kocaeli (In Turkish).Kutay, M.G., 2003. Guide for Manufacturer. Birsen Press, Istanbul (In Turkish).Gunay, D., 1993. Fundementals of Finite Element Method forEngineers.(translation), Sakarya University, Press no:03, Sakarya (In Turkish).Ozmerzi, A., 2001. Mechanization of Garden Plants. Akdeniz University, Press no:76, Antalya (In Turkish).。