考虑磨损与变形的谐波齿轮精度可靠性分析与优化设计

针对谐波齿轮减速器中存在的磨损和变形因素导致减速器传动精度低、可靠性差等问题,建立考虑磨损与变形的谐波齿轮减速器传动误差模型,并进行精度可靠性分析与优化设计。通过分析传动误差的影响因素建立了传动误差模型;基于磨损经验模型和试验数据,应用贝叶斯修正方法建立动态磨损模型,同时根据试验数据和高斯过程回归建立柔轮变形模型;综合获得的传动误差模型、磨损模型和柔轮变形模型建立谐波齿轮精度可靠性模型,并应用基于拉丁超立方抽样的Kriging代理模型和蒙特卡洛法求解某谐波齿轮减速器传动精度可靠度。最后采用序列二次规划法对谐波齿轮减速器进行优化设计。优化结果表明,在工况参数(输出端负载17.5 N·m,输入端转速100 r/min)下,优化后的谐波齿轮减速器在工作时间3 000 h处的可靠度达到99.02%,相比未优化前提升7.85%,而成本却只增加1.70%。     

机器人用高精度RV减速器曲轴误差

机器人用高精度RV(Rotate Vector)减速器的曲轴存在制造装配误差,为了保证RV减速器的传动精度、承载能力、总体回差和传动效率等要求,必须控制曲轴的设计精度.分析了曲轴偏心距和偏心距误差对RV减速器传动精度的影响,建立了曲轴偏心距和偏心距误差影响的数学模型,使用MATLAB进行了仿真计算.结果表明:某型RV减速器曲轴偏心距应为1.3mm,其偏心距误差负向分布有助于提高精度,加载后有助于减小回差间隙.     

基于刚柔耦合的RV减速器传动精度仿真与试验研究

建立包含加工误差、装配误差、弹性变形以及间隙的RV减速器刚柔耦合虚拟样机模型。对虚拟样机模型进行尺寸、误差变量参数化,得到不同制造装配误差因素单独作用下RV减速器的传动误差曲线,确定对整机传动精度影响较大的误差因素。针对主要误差因素,通过正交试验,分析多误差耦合时RV减速器传动精度变化情况。采用光栅法对RV减速器进行传动精度测试,对比试验与仿真分析结果,修改并验证仿真模型。     

谐波减速器传动误差的研究

由于谐波传动本身的复杂性,很难给出完全符合实际的传动误差计算公式,而传统的谐波减速器的传动误差估算公式往往要比实验测得的数据小很多。因此,针对谐波传动误差计算式的改进很有必要。从制造安装误差、理论瞬时传动比不稳定、侧隙等因素出发,推导建立谐波齿轮减速器的传动误差计算公式。结合具体实例计算得到谐波齿轮减速器的传动误差理论值,并通过实验验证了计算公式的正确性。     

基于正交试验法的RV减速器传动误差分析

利用Pro/E建立实体装配模型,导入到ADAMS中建立虚拟样机,基于正交试验法采用直观分析法和方差分析法比较针齿中心圆半径误差、摆线轮移距和等距修形量、偏心距误差和针齿半径误差对RV减速器传动误差的影响,并针对影响因素推导出传动误差的计算公式,结果表明针齿中心圆半径误差对RV减速器传动误差影响最大,偏心距误差对RV减速器传动误差影响最小,与仿真试验结果对比表明传动误差计算公式正确可靠。     

偏心误差对滤波减速器传动误差的影响研究

介绍了少齿差滤波减速器的结构及传动原理;基于几何尺寸关系的微分模型,推导了滤波减速器受其偏心轴、双联齿轮、固定齿轮等构件回转中心偏心误差影响的传动比计算式,运用微分方程的数值解法得出了传动误差的变化曲线;对滤波减速器的传动误差进行了测试,实验验证了偏心传动计算方法的正确性。     

空间谐波减速器的可靠性研究

针对谐波减速器在空间低速、轻载的工况下,由于磨损引起传动误差、回差超过要求精度的失效模式,首先建立了考虑磨损量的谐波减速器的传动误差和回差的计算模型,并由此建立了谐波减速器的可靠性模型。根据所建立的可靠性模型进行了实例分析,并编写MATLAB程序进行了计算。结果表明,所建立的谐波减速器可靠性模型是符合实际情况的。     

基于权重系数的谐波减速器公差设计

公差设计作为谐波减速器设计中的关键环节，对整机的传动精度和加工性能具有重要影响，当前谐波减速器的公差大都基于经验设计，为此提出了一种基于权重系数的谐波减速器的公差设计方法。对主要误差因素进行全局敏感性分析构建各误差因素的敏感性权重系数，利用三角模糊层次分析法(TFAHP)对加工难易度进行分析获得加工难易度权重系数，采用几何平均数法综合敏感性权重系数与加工难易度权重系数得到总权重系数，由此求解各误差因素的许用传动误差分量，从而得到公差设计值实现谐波减速器的公差分配设计。实例分析表明该方法在保证谐波减速器传动精度的同时，可根据加工难易度调整公差值，有利于降低加工难度及成本，为工程中谐波减速器的公差设计提供理论指导。     

谐波减速器传动机构的动态仿真研究

为了研究谐波减速器在实际工作状态下的变形情况,利用Adams对模型进行动态仿真.谐波减速器齿轮均采用双圆弧齿形,因此首先对齿形进行设计,并通过solidworks建立谐波传动装置各零部件的模型.然后在AnsysWorkbench中对柔轮进行静力学分析,查看柔轮的应力分布以及变形情况.最后利用Adams建立谐波减速器的刚柔混合模型,实现柔轮和刚轮的动态仿真.通过仿真分析可以看到谐波减速器的传动过程比较平稳,柔轮与刚轮轮齿之间的啮合情况良好,因此可以说明减速器的传动机构设计合理.     

谐波减速器的传动精度分析

以某舵机齿啮式谐波齿轮减速器为研究对象,分析了影响其传动精度的误差源,在忽略伞齿轮副的高频误差和齿啮式输出误差的前提下,对谐波齿轮副的传动误差进行了理论计算,用谐波传动精度动态检测仪测量了整个减速器的传动链误差.结果表明计算值与测得值基本吻合,两者误差在10％以内,说明假设前提条件成立,为设计从理论上提高谐波减速器的传动精度提供本参考,具有实际应用价值。     

用于抽油机的新型两级三环减速器的振动分析

为解决一般三环减速器振动大、温升高和转臂轴承使用寿命短等生产中迫切需要解决的问题,依据功率分流、弹性环均载、同步带缓冲及吸振和机构平衡原理,设计出了一种具有圆弧齿同步带传动的完全平衡、均载减振,偏心相位差为180°的新型三环减速器。该两级三环减速器的传动效率达93%以上,载荷分配不均匀系数小于1.1,振动加速度值也小于同等传动能力的一般三环减速器。依据振动理论建立了具有弹性支撑的输出轴的动力学分析模型,根据周期函数的傅里叶级数展开原理,将复杂的激振力分解成为多个频率成整倍数关系的简谐激励函数,导出了动态响应表达式,结果表明,当载荷分配不均匀系数为1.0时的输出轴两端支撑同步。该新型减速器可用作抽油机的传动装置。     

基于COSMOSworks的摆线针轮减速器有限元分析

针对摆线针轮减速器的摆线轮齿廓形状复杂、加工制造难度大等同题,根据摆线成形原理及设计要求,利用SolidWorks软件建立了摆线针轮减速器三维模型,运用COSMOSworks有限元分析软件模拟了减速器的工作状态,并对其主要部件进行了有限元分析,为摆线针轮减速器的结构设计提供了参考依据。研究结果表明,运用该设计方法对提高摆线针轮减速器设计的速度和质量具有一定的实际意义。     

Error Compensation of Thin Plate-shape Part with Prebending Method in Face Milling

Low weight and good toughness thin plate parts are widely used in modern industry, but its flexibility seriously impacts the machinability. Plenty of studies focus on the influence of machine tool and cutting tool on the machining errors. However, few researches focus on compensating machining errors through the fixture. In order to improve the machining accuracy of thin plate-shape part in face milling, this paper presents a novel method for compensating the surface errors by prebending the workpiece during the milling process. First, a machining error prediction model using finite element method is formulated, which simplifies the contacts between the workpiece and fixture with spring constraints. Milling forces calculated by the micro-unit cutting force model are loaded on the error prediction model to predict the machining error. The error prediction results are substituted into the given formulas to obtain the prebending clamping forces and clamping positions. Consequently, the workpiece is prebent in terms of the calculated clamping forces and positions during the face milling operation to reduce the machining error. Finally, simulation and experimental tests are carried out to validate the correctness and efficiency of the proposed error compensation method. The experimental measured flatness results show that the flatness improves by approximately 30 percent through this error compensation method. The proposed method not only predicts the machining errors in face milling thin plate-shape parts but also reduces the machining errors by taking full advantage of the workpiece prebending caused by fixture, meanwhile, it provides a novel idea and theoretical basis for reducing milling errors and improving the milling accuracy.     

钛合金薄壁微铣削精度研究现状与发展趋势

随着航空、航天、船舶等工程领域对具有薄壁结构的钛合金零件需求的不断提高,加工效率相对较高且适用于曲面等复杂几何形状制造的微铣削加工方法在钛合金薄壁加工中获得了广泛的应用。然而由于其刚度较低,在微铣削加工钛合金薄壁时极易产生工件变形、失稳和振动等问题,并导致加工精度的下降。为此从理论建模、有限元仿真和试验测量三个方面分析了国内外弱刚度金属薄壁微铣削技术研究的现状。相关研究表明,在加工过程中对薄壁变形进行准确预测对于薄壁微铣削加工误差补偿模型的建立与薄壁加工精度的提高具有重要意义。并指出,在获得数学规律的基础上对薄壁微铣削加工变形和该变形对加工精度造成的影响之间蕴含的物理关系仍有待进一步的研究。     

Load Sharing Behavior of Star Gearing Reducer for Geared Turbofan Engine

Load sharing behavior is very important for power-split gearing system, star gearing reducer as a new type and special transmission system can be used in many industry fields. However, there is few literature regarding the key multiple-split load sharing issue in main gearbox used in new type geared turbofan engine. Further mechanism analysis are made on load sharing behavior among star gears of star gearing reducer for geared turbofan engine. Comprehensive meshing error analysis are conducted on eccentricity error, gear thickness error, base pitch error, assembly error, and bearing error of star gearing reducer respectively. Floating meshing error resulting from meshing clearance variation caused by the simultaneous floating of sun gear and annular gear are taken into account. A refined mathematical model for load sharing coefficient calculation is established in consideration of different meshing stiffness and supporting stiffness for components. The regular curves of load sharing coefficient under the influence of interactions, single action and single variation of various component errors are obtained. The accurate sensitivity of load sharing coefficient toward different errors is mastered. The load sharing coefficient of star gearing reducer is 1.033 and the maximum meshing force in gear tooth is about 3010 N. This paper provides scientific theory evidences for optimal parameter design and proper tolerance distribution in advanced development and manufacturing process, so as to achieve optimal effects in economy and technology.     

Mesh Force Modelling and Parametric Studies for Compound Oscillatory Roller Reducer

A compound oscillatory roller reducer (CORR) with a first-stage gear transmission and a second-stage oscillatory roller transmission is presented.The transmission principle of oscillatory roller transmission is introduced,and the tooth profile equation of the inner gear is derived.The analytical model of mesh force considering the installation errors and manufacturing errors is proposed.Then,parametric studies considering different errors on the mesh force are con-ducted.Results show that the design parameters are significant factors for mesh force.The mesh force is reduced by 17％ as the eccentricity of disk cam increases from 2.5 mm to 4 mm.When the radius of the movable roller increases from 7 mm to 20 mm,the mesh force decreases by 8％.As the radius of disk cam increases from 125 mm to 170 mm,the mesh force is decreased by 26.5％.For the impacts of errors,the mesh force has a noticeable fluctuation when these errors exist including the manufacturing error of disk cam,the installation error of disk cam and the manufactur-ing error of movable roller change.The prototype of the reducer is manufactured and preliminary run-in test proved the feasibility of the transmission principle.     

Research on dynamic transmission error of harmonic drive with uncertain parameters by an interval method

Transmission error is one of the most important performance indicators for evaluating harmonic drives, and can have crippling effects on positioning accuracy and stability of industrial robots. However, most of the existing error analysis methods focus on a single factor, and do not consider the uncertainty of dynamic parameters, leading to evident limitations. In the present study, static transmission error (caused by manufacturing and assembly error) and dynamic transmission error (generated by static transmission error and dynamic parameters) of a harmonic drive are modeled. An interval method is developed and used to numerically express uncertain dynamic parameters of the system. Chebyshev polynomials are used to approximate the dynamic differential equations of the harmonic drive, and then the distribution of dynamic transmission error and its relationship with uncertain parameters are discussed in detail. In addition, a global sensitivity analysis is carried out to intuitively demonstrate how much impact each parameter has on dynamic transmission error. Our results suggest that the moment of inertia J_in and the torsional stiffness coefficient k₁ have a large influence on dynamic transmission error. Finally, the proposed method is validated by experiment. The method can be adopted to determine the upper and lower bounds of dynamic transmission error of dynamic systems under the influence of uncertain parameters and provides a theoretical basis for transmission error optimization and compensation.