高速重载斜齿圆柱齿轮传动的参数对性能的影响研究

基于刀具进行齿轮参数选取的传统设计方法,对于高速重载齿轮传动很难满足振动冲击小、质量轻等性能要求。基于齿轮传动的性能要求,建立了高速重载齿轮传动的参数直接设计方法。采用动载系数、最大接触应力和滑移率描述齿轮传动的性能指标,考察齿顶高系数、压力角、螺旋角、齿数比以及变位系数对齿轮性能的影响,为进行齿轮直接设计方法和参数优化奠定了理论基础。结果表明,增大齿顶高系数和螺旋角、减小压力角可以减小动载系数使得齿轮传动中的噪声和冲击减少;增大齿顶高系数、压力角和螺旋角可以减小齿面接触应力;减小齿数比可以减小滑移率;减小齿面接触应力和滑动率并在等滑移率曲线上选取变位系数能够避免齿面胶合和传动失效。

基于LMS工作模态测试的齿轮箱性能分析

基于LMS测试分析系统,对某试验齿轮箱进行工作模态测试和分析;采用最小二乘复频域法对齿轮箱各阶模态进行参数识别,并对工作模态分析过程中额外输入峰进行了辨识,剔除了谐波引起的虚假模态;通过对测试结果进行分析及讨论,发现齿轮安装偏心导致齿轮啮合频率及其谐波的分布;根据各阶模态振型的特性,对齿轮箱运行状况进行评价,提出对该齿轮箱结构设计的改进措施。

高性能同轴式磁力齿轮结构设计与实验研究

为了改善磁力齿轮的扭矩传递能力,研究了一种采用鼠笼式调磁装置的同轴式磁力齿轮。通过建立磁力齿轮的瞬态分析有限元模型,模拟分析得到内外气隙长度、永磁体厚度和长径比等结构参数对其传递扭矩能力的影响规律曲线,并得出了机构参数的优化值,模拟了该参数下磁力齿轮的运行情况。基于优化值制作实验样机进行实验研究,实验结果表明,采用此种调磁极片能够实现定传动比传动并能传递一定的扭矩。实验结果与模拟分析具有相似性,表明优化的结构参数能够保证磁力齿轮扭矩传递能力。

高性能齿轮关键制造技术现状及发展建议

热处理应用技术直接影响齿轮产品性能,随着我国对高端齿轮需求的增长,齿轮基础制造工艺的开发研究非常重要。该文介绍了齿轮深冷处理、离子齿面注入、表面涂层及齿面超精加工等几项高性能齿轮制造新技术,提出采用各种新的处理技术的同时,也应对传统技术进行开发升级,以及采用复合技术,提高高端齿轮产品的制造质量,满足市场需求。并对高性能齿轮关键制造技术的深化研究及推广应用提出了若干建议。

轧机稀油润滑系统齿轮油性能指标提升研究

为提升在线齿轮油性能指标,综合分析了现场各润滑系统的特点,寻找出一种简单易行的能够提升齿轮油性能指标的操作方法,既为关键部位机械设备提供了良好的润滑保障,又能够避免齿轮油长期使用指标劣化造成的报废损失。

合金材料中不同金属元素对齿轮机械性能和热处理的影响

合金是由各种金属元素融合均匀再经冷凝而形成,具有比单一金属更好的机械性能及化学性能。在齿轮制造中用合金来作齿轮组织的材料,可以增强齿轮的机械性能,降低磨损程度。合金可以是单一、多种的金属元素,不同的金属成分对齿轮的机械性能和热处理性能影响也会不同。为提高齿轮的机械性能和热处理性能,对比常用合金材料中不同金属元素配比,以发现不同齿轮用合金材料的优点。

变速箱齿轮冲击性能分析方法的研究

经济和科技的飞速发展让我国所有产业都发生了一定的影响,尤其体现在人们生活水平的提升,对车辆的需求量加大。而对于汽车自身来说,车辆的变速箱是非常容易出现问题的,高负荷的工作状态下,齿轮自身所承受的压力增加,非常容易造成齿轮失效。

磁力齿轮中调磁极片结构参数的数值模拟分析

为了改善磁力齿轮的转矩传递能力，研究调磁极片的调磁机理和结构要求，提出3种结构形式．针对调磁极片层叠结构出现的转矩传递能力不足等问题，采用瞬态有限元分析方法对调磁极片各部分的结构参数进行数值模拟．结果表明：磁力齿轮的输出转矩随调磁极片相对齿宽的增加先增大后减小，当相对齿宽在0．4～0．5时转矩较大，且变化相对平稳；磁力齿轮的输出转矩随调磁板片齿高的增加也是先增大后减小，在齿高为3mm时为最大，比试验参数下的模拟结果提高18％；输出转矩随着连接桥高度的增大而减小，消除连接桥可使输出转矩比试验参数下的模拟结果提高62％．

高性能齿轮基础数据研究

齿轮基础数据指在齿轮设计、制造、运维等过程中的关键材料、结构、性能等指标参数,是高性能齿轮传动主动设计的关键因素,也是当前国内外齿轮行业技术差距累积最显著的环节.针对高端装备极端环境高可靠、长寿命服役的需求,开展了面向我国材料与工艺环境的传动系统的高性能齿轮表面完整性与抗疲劳设计制造研究,提出了基于集成学习和数据增强的小样本齿轮疲劳试验评价方法,试验时间与样本需求显著降低;建设了16Cr3NiWMOVNbE、9310、18CrNiMo7-6、42CrMo、20Cr2Ni4A等齿轮材料疲劳S-N曲线、强度极限、胶合极限、表面完整性参数等基础数据10000余条,开发了涵盖材料、工艺、结构、性能等500余项参数的高性能齿轮基础数据库软件,齿轮基础数据治理效率明显提升;开发了温度-应力-振动多维信号无线采集分析技术与装置,探索了高性能齿轮渗碳磨削、喷丸强化、微粒喷丸、滚磨光整、离子注入、热障涂层等高表面完整性创成机理与加工技术,实现齿轮接触疲劳/弯曲疲劳/胶合极限相比ISO标准显著提高,极大推动齿轮传动轻量化创新,为我国下一代高端装备提供高性能基础件基础数据储备.

高性能磁力齿轮传动性能的动态仿真分析与实验研究

针对一台永磁内转子极对数为7,永磁外转子极对数为15的高性能磁力齿轮,为了研究其传动性能,讨论了磁力齿轮的3种运行方式,推导了其传动比关系,并在此基础上,推导了传动效率、转矩与传动比之间的关系公式;在转速较低的情况下,当传动效率为1,输出转矩仅为输入转矩与传动比的乘积。为此,运用有限元软件,对3种运动方式在转速较低的情况下分别进行了双转子转动时的动态仿真分析,得到了不同负载对转矩的影响。最后通过传动性能实验装置进行实验验证,测得不同负载下磁力齿轮的转矩。结果表明,在转速较低的情况下,输入转矩随着输出转矩的增大成线性增加,且输出转矩与输入转矩的比值近似等于传动比的值,这一研究可用于在传动比已知情况下的动态转矩的估算。

基于减小热处理畸变的20CrMnMoH高性能齿轮预先热处理工艺

采用理论分析和实验研究相结合的方法,对20CrMnMoH齿轮钢在预先热处理过程中产生贝氏体非平衡组织的现象进行了分析研究。结果表明:20CrMnMoH齿轮钢在常规预先热处理过程中的冷却速度无法控制,过冷奥氏体进行非平衡组织转变,容易得到贝氏体等非平衡组织。根据贝氏体等非平衡组织的组织遗传效应,结合过冷奥氏体等温转变的原理和机制,设计了两次等温正火预先热处理工艺,首次等温正火预先热处理完成了非平衡组织到平衡组织的转变,二次等温正火预先热处理实现了晶粒的细化和均匀化。通过工艺优化控制实现了齿轮锻件的金相组织为1~2级、同批次不同齿轮锻件硬度差≤5 HB的技术指标。成品齿轮的精度可以达到6级,验证了预先热处理对减小齿轮热处理畸变、提高齿轮精度的有效性。

Thermo-structural analysis on evaluating effects of friction and transient heat transfer on performance of gears in high-precision assemblies

The high precision assemblies with considerable radial interference should be accompanied by heating and cooling processes.However,the mechanical properties of metals are greatly affected by thermal operations.So,for evaluating the stress distribution and distortion of teeth profiles in a gear/shaft assembly,a transient thermal analysis is necessary for finding the change in mechanical properties.The friction on the contact surface is another important parameter in interaction of the gear with the shaft.Evaluating the gear stress and deformation fields for several modes of heat transfer and friction coefficients showed that the maximum radial or tangential stresses on contact surface of the joint may have more than 8%increase by increasing friction coefficient;while the intensity of heat transfer at cooling stage has lower effect on stress distribution.

Finite Element Analysis of Internal Gear in High-Speed Planetary Gear Units

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. Six evenly spaced linear springs are used to describe the fitting status between 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.

Effect of gear teeth finishing method on properties of teeth surface layer and its resistance to pitting wear creation

This work presented the characteristics of two gear teeth finishing methods, due to the properties of gear teeth surface layer obtained at the tooth working depth. These methods are: 1) the teeth carburization, hardening to a hardness of HRC 60-62 and then grinding, 2) the soft gear shaving as the final mechanical treatment and then carburizing and hardening to the hardness of HRC60-62. This work included the test results of the contact fatigue strength carried out on the circulating power system. The Wohler curves were plotted due to the obtained results, as the basis for the practical evaluation of the considered gear finishing methods. The parameters like volume distribution of the voids, content of the retained austenite, compressive residual stress value, but also the results of contact fatigue strength tests, are more favorable for the teeth shaving method than for the teeth grinding method.

Influence of cutter diameter on meshing performance in spiral bevel gears

Playing a critical role in transmitting movement and power, the meshing performance of spiral bevel gears has a significant effect on products' operational performance. To evaluate the meshing performance, the accurate three-dimensional(3D) spiral bevel gear models are established through the Pro/E and MATLAB softwares, and the finite element analysis(FEA) methods are applied to the theoretical investigation of the influence of cutter diameter on meshing performance in spiral bevel gears. The results obtained show that the cutter diameter has a significant influence on spiral bevel gears' meshing performance, such as the contact area, contact pressure, bending stress, torsional stiffness and transmission error.

Energy control strategy for parallel hydrostatic transmission hybrid vehicles

Aimed at the relatively lower energy density and complicated coordinating operation between two power sources,a special energy control strategy is required to maximize the fuel saving potential.Then a new type of configuration for hydrostatic transmission hybrid vehicles(PHHV) and the selection criterion for important components are proposed.Based on the optimization of planet gear transmission ratio and the analysis of optimal energy distribution for the proposed PHHV on a representative urban driving cycle,a fuzzy torque control strategy and a braking energy regeneration strategy are designed and developed to realize the real-time control of energy for the proposed PHHV.Simulation results demonstrate that the energy control strategy effectively improves the fuel economy of PHHV.

An intelligent method for contact fatigue reliability analysis of spur gear under EHL

To complete the contact fatigue reliability analysis of spur gear under elastohydrodynamic lubrication(EHL) efficiently and accurately, an intelligent method is proposed. Oil film pressure is approximated using quadratic polynomial with intercrossing term and then mapped into the Hertz contact zone. Considering the randomness of the EHL, material properties and fatigue strength correction factors, the probabilistic reliability analysis model is established using artificial neural network(ANN). Genetic algorithm(GA) is employed to search the minimum reliability index and the design point by introducing an adjusting factor in penalty function. Reliability sensitivity analysis is completed based on the advanced first order second moment(AFOSM). Numerical example shows that the established probabilistic reliability analysis model could correctly reflect the effect of EHL on contact fatigue of spur gear, and the proposed intelligent method has an excellent global search capability as well as a highly efficient computing performance compared with the traditional Monte Carlo method(MCM).

Noise reduction effect of airfoil and small-scale rotor using serration trailing edge in a wind tunnel test

This paper discussed a noise reduction effect of airfoil and small-scale model rotor by using attached serration trailing edge in the wind tunnel test condition. In order to analyze the changes in the performance due to the inclusion of a serrated trailing edge designed to reduce noise, a 10 k W wind turbine rotor was equipped with a thin serrated trailing edge. The restrictive condition for the serrated trailing edge equipped with the using of a 2D airfoil was examined through the using of a wind tunnel experiment after studying existing restrictive condition and analyzing prior research on serrated trailing edges. The aerodynamic performance and noise reduction effect of a small-scale model were investigated with the using of a serrated trailing edge. Moreover, the noise levels from the experiment were considered that the noise prediction method could be used for a full-scale rotor. It is confirmed that noise reduction effect is compared with wind tunnel test data at the 2D airfoil and model rotor condition.

Mesh stiffness evaluation of an internal spur gear pair with tooth profile shift

Tooth profile shift will change the thickness of gear teeth and a part of geometrical parameters of a gear pair, thus influencing its mesh stiffness and consequently the dynamic performances. In this paper, an analytical mesh stiffness calculation model for an internal gear pair in mesh considering the tooth profile shift is developed based on the potential energy principle. Geometrical representations of the tooth profile shift are firstly derived, and then fitted into the analytical tooth stiffness model of gears. This model could supply a convenient way for mesh stiffness calculation of profile shifted spur gears. Then, simulation studies are conducted based on the developed model to demonstrate the effects of tooth profile shift coefficient on the tooth compliances and the mesh stiffness of the internal spur gear pair. The results show that tooth profile shift has an obvious influence on the mean value, amplitude variation and phase of the mesh stiffness, from which it can be predicted that the dynamic response of an internal gear transmission system will be affected by the tooth profile shift.