基于虚拟制造的弧齿锥齿轮仿真加工技术研究

通过分析弧齿锥齿轮加工原理及弧齿锥齿轮铣齿机的结构和运动关系,建立了弧齿锥齿轮铣齿机虚拟机床模型及虚拟机床加工坐标系,推导了弧齿锥齿轮铣齿机虚拟机床运动参数的计算方法,构建了弧齿锥齿轮仿真加工模型.计算了一对弧齿锥齿轮进行的几何参数、刀具参数和虚拟机床运动参数,并通过弧齿锥齿轮铣齿机虚拟机床对其进行了仿真加工,验证了弧齿锥齿轮铣齿机虚拟机床模型及仿真加工模型的正确性.     

基于Workbench的斜齿轮固有特性分析

采用Pro/E建立了一对斜齿轮的啮合模型,通过有限元分析软件Workbench的高效率模型导入功能实现了Pro/E和Workbench的联合仿真,分别对未定义齿面接触的斜齿轮啮合模型和定义齿面接触的斜齿轮啮合模型进行了模态分析,提取了两种模型的前6阶固有频率和主振型,并研究了螺旋角β的变化对于接触齿轮副固有特性的影响,为复杂斜齿轮系统的进一步分析奠定了基础。     

渐开线斜齿圆柱齿轮弹流润滑模型的建立

渐开线直齿圆柱齿轮的弹流润滑问题已经基本成熟，而对同样是线接触的渐开线斜齿圆柱齿轮的弹流润滑求解却研究甚少并颇有争议。分析了斜齿轮齿廓曲面的形成及啮合特点，建立了研究渐开线斜齿圆柱齿轮弹流润滑的物理模型和数学模型．通过数学推导，得到了膜厚方程，通过多重网格法即可获得渐开线斜齿圆柱齿轮在某一瞬时的弹流润滑数值解。     

Dynamic analysis of three-dimensional helical geared rotor system with geometric eccentricity

A dynamic model of a multi-shaft helical geared rotor system is presented. Rotating shafts of the system are modeled as Timoshenko beams. A general three-dimensional dynamic model of helical gear pairs with geometric eccentricity is developed for the gear mesh and bearing flexibility is included in the model as well. The transmission error and gear geometric eccentricity are simulated as excitations. Eigenvalue solution and the modal summation technique are used to predict the natural frequencies and forced responses of the system. Then two geared rotor system models are presented for validation of the gear dynamic model. It is demonstrated that the gear mesh model is effective for general geared rotor systems, spur and helical gears, one-stage and multi-stage systems. Finally, forced responses of an example system are analyzed to demonstrate the influences of the helical gear geometric eccentricity and the coupling between gear geometric eccentricity and rotor mass unbalance.     

Mathematical model of a helical gear with asymmetric involute teeth and its analysis

This paper describes a simple approach based on the gear theory for deriving a helical gear with asymmetric involute teeth. A helical gear with asymmetric involute teeth can be easily obtained through the envelope theory for the one-parameter family of surfaces. The mathematical models for asymmetric helical gears can be provided by the application of two imaginary rack cutters. The investigation on the undercutting analysis of the asymmetric helical gear is studied based on the developed mathematical model and the method of tooth-profile shifting. Here we provide geometric modeling of the designed asymmetric helical gear meshing when assembly errors are present. Stress analysis for the helical and the cylindrical forms are constructed. To illustrate the effectiveness of the approach, an analytical expression of helical gear with asymmetric involute teeth is given.     

Mathematical model of a helical gear with asymmetric involute teeth and its analysis

This paper describes a simple approach based on the gear theory for deriving a helical gear with asymmetric involute teeth. A helical gear with asymmetric involute teeth can be easily obtained through the envelope theory for the one-parameter family of surfaces. The mathematical models for asymmetric helical gears can be provided by the application of two imaginary rack cutters. The investigation on the undercutting analysis of the asymmetric helical gear is studied based on the developed mathematical model and the method of tooth-profile shifting. Here we provide geometric modeling of the designed asymmetric helical gear meshing when assembly errors are present. Stress analysis for the helical and the cylindrical forms are constructed. To illustrate the effectiveness of the approach, an analytical expression of helical gear with asymmetric involute teeth is given.     

斜齿轮副动态特性对支承结构参数的灵敏度

针对斜齿轮副动特性的灵敏度问题 ,考虑轴和轴承的柔性以及由于轮齿啮合而产生的横向运动、扭转运动、轴向运动与旋转 (摆动 )运动间的动态耦合的影响 ,建立了斜齿轮传动系统的动力学模型 ,推导了固有频率及动态啮合挠度相对于斜齿轮副支承结构参数的灵敏度计算公式 ,并给出了实例。这一方法可用于斜齿轮传动系统的动态优化设计及改进设计     

斜齿非圆齿轮滚齿加工最简数学模型与联动控制结构

为了解决斜齿非圆齿轮的制造难题,探讨斜齿非圆齿轮数控滚齿加工的最简数学模型与机床应该具有的联动结构.介绍了斜齿非圆齿轮齿廓的形成原理,综合运用螺旋齿啮合原理和工具斜齿条法,推导出斜齿非圆齿轮滚齿加工的最简数学模型,它是一个四坐标联动的结构.利用研发出的专用电子齿轮电路模板和脉冲合成电路模板,设计出斜齿非圆齿轮滚齿加工所...     

Effects of different coupling models of a helical gear system on vibration characteristics

Time-varying mesh stiffness (TVMS) and the dynamic coupling between the helical gears have a great influence on the vibration characteristics of a helical gear rotor system. Considering the effects of TVMS and adopting two coupling models (lateral-torsional coupling model and lateral-torsional-axial-swing coupling model), the dynamic behavior of a helical gear system was studied. First, an analytical model was used to analyze TVMS of a helical gear pair where the helical tooth is simulated by many spur tooth slices along the direction of the tooth width and the mesh stiffness of each slice is calculated using the energy method. Then, considering the effects of the TVMS excitation, the finite element model of a helical gear rotor system was established. Gear mesh was simulated by the above-mentioned two coupling models to investigate the effects of coupling forms on the system vibration characteristics. The strain energy was used to distinguish the dominant mode and dominant shaft of a gear system in natural characteristics analysis. The results show that the full coupling model can analyze accurately the vibration characteristics of the system and the axial and swing motions cannot be ignored in vibration analysis. Finally, the effects of helix angle on TVMS and vibration responses of a helical gear system were also studied.     

用工具斜齿条法加工斜齿非圆齿轮的啮合理论模型

介绍了斜齿非圆齿轮齿廓的形成原理,针对用工具斜齿条法加工斜齿非圆齿轮动轴线变传动比复杂的运动几何关系,建立了其理论研究的数学模型,对斜齿非圆齿轮齿廓端面截形、节曲柱面截形及瞬时接触线进行了分析。论证了斜齿非圆齿轮齿廓为直纹面,其节曲柱面截形是变导程等螺旋角的螺旋线,平行轴斜齿非圆齿轮传动的瞬时接触线是直线。     

非共轴螺旋后刀面微钻的五轴联动刃磨方法及其钻削性能研究

微细钻头的几何结构是影响刀具钻削性能和微孔加工质量的关键因素。非共轴螺旋面钻尖由连续的螺旋后刀面组成,相比平面钻尖能有效的提高刀具的刃磨效率及其钻削性能。针对非共轴螺旋面钻尖,推导后刀面形成过程中螺旋运动发生线的位置方程,建立了基于砂轮和钻头接触线的后刀面数学模型。根据六轴数控工具磨床的运动原理,提出非共轴螺旋后刀面五轴联动刃磨方法。分析砂轮与螺旋槽之间的相对运动关系,提出微细钻头螺旋槽的数控加工方法。进行非共轴螺旋后刀面微钻的刃磨试验,验证了该刃磨方法的可行性。进而采用制备出的具有相同几何结构参数的平面、锥面和非共轴螺旋面微细钻头进行不锈钢钻削试验,结果表明非共轴螺旋面和锥面微钻的钻削力、后刀面磨损明显小于平面微钻,并且非共轴螺旋后刀面微钻的横刃磨损程度小于平面和锥面微钻。研究证实了所提出的五轴联动刃磨方法可以有效地制备出较高钻削性能的非共轴螺旋后刀面微细钻头。     

交错轴斜齿轮齿面接触区的计算机辅助分析

建立了交错轴斜齿轮啮合分析的数学模型。通过对不同基本参数的交错轴斜齿轮传动进行系统研究,找出了交错轴斜齿轮基本参数对其啮合特性的影响规律;提出小轴交角条件下,可以采用一直齿轮、一斜齿轮的齿轮副组合方式;给出了大轴交角条件下啮合性能不良的改进措施;说明交错轴斜齿轮不仅能传递运动,而且能传递动力。     

基于APDL的斜齿轮造型技术

在斜齿轮的CAE分析中,需要对它进行参数化造型,为实现这一目的,利用了ANSYS的APDL.首先在ANSYS中形成端面齿廓,再沿螺旋线拖拉,直接生成了一对斜齿轮的参数化模型,便于进一步分析齿轮的齿面接触应力和齿根应力,以及斜齿轮的啮合过程,在实际中应用获得了良好的效果.     

Modelling, simulation and experimental investigation of cutting forces during helical milling operations

The kinematics of helical milling on a three-axis machine tool is first analysed. An analytical model dealing with time domain cutting forces is proposed in this paper. The cutting force model is established in order to accurately predict the cutting forces and torque during helical milling operations as a function of helical feed, spindle velocity, axial and radial cutting depth and milling tool geometry. The forces both on the side cutting edges and on the end cutting edges along the helical feed path are described by considering the tangential and the axial motion of the tool. The dual periodicity which is caused by the spindle rotation, as well as the period of the helical feed of the cutting tool, has been included. Both simulation and experiments have been performed in order to compare the results obtained from modelling with experiments.     

混合标架下宽斜齿轮三维接触有限元前处理技术

本文针对宽斜齿轮，采用混合标架，建立了轮齿在各个不同位置的啮合时的有限元网格自动生成的算法；并开发了模块化；结构化，参数化的前处理程序，只需输入齿轮基本参数，即可得到完整的轮齿三维接触有限元分析数据文件，本文程序使用方便，适于在工程设计推广使用。     

基于Pro/E的非对称渐开线斜齿圆柱齿轮参数化设计及应力分析

非对称渐开线斜齿圆柱齿轮作为一种新型的齿轮,目前对其还没有展开详细的研究。从齿轮范成法加工角度出发,根据齿条型刀具上各曲线部分参数,推导求得非对称渐开线斜齿圆柱齿轮端面主动侧、从动侧的渐开线、齿根过渡曲线方程。以轮齿端面曲线方程为基础,结合三维造型软件Pro/E,建立出非对称渐开线斜齿圆柱齿轮的三维模型。由于建立后的齿轮模型已经参数化,通过更改基本参数,可以快速生成需求的齿轮。同时,以建立的模型为基础,结合有限元分析软件,对对称与非对称渐开线斜齿圆柱齿轮两个特殊啮合位置的轮齿齿根弯曲强度进行了分析、比较。     

Prediction of cutting forces in helical milling process

The prediction of cutting forces is important for the planning and optimization of machining process in order to reduce machining damage. Helical milling is a kind of hole-machining technique with a milling tool feeding on a helical path into the workpiece, and thus, both the periphery cutting edges and the bottom cutting edges all participated in the machining process. In order to investigate the characteristics of discontinuous milling resulting in the time varying undeformed chip thickness and cutting forces direction, this paper establishes a novel analytic cutting force model of the helical milling based on the helical milling principle. Dynamic cutting forces are measured and analyzed under different cutting parameters for the titanium alloy (Ti–6Al–4V). Cutting force coefficients are identified and discussed based on the experimental test. Analytical model prediction is compared with experiment testing. It is noted that the analytical results are in good agreement with the experimental data; thus, the established cutting force model can be utilized as an effective tool to predict the change of cutting forces in helical milling process under different cutting conditions.     

玉米秸秆切碎滚筒螺旋刀片的有限元分析

玉米青贮机的运用日益广泛,其中动刀片是玉米秸秆切碎滚筒的主要工作零件,其质量和寿命直接影响玉米青贮机的切碎性能和生产率,其中螺旋形动刀片目前理论研究尚少。对切碎滚筒的各项参数进行了确定,对螺旋刀片进行了设计,并应用三维造型软件Pro/E对其进行了三维模型建立。应用有限元分析软件ANSYS,对螺旋刀片进行了应力分布和变形计算分析,分析了应力集中的原因,提出了提高螺旋刀片寿命的措施,为螺旋刀片的进一步研究提供了理论依据。     

基于Pro/E的角变位斜齿轮参数化精确建模研究

综合运用Pro/E软件的参数化技术对渐开线角变位斜齿轮参数化的精确建模设计进行了研究,以角变位斜齿轮加工和渐开线齿廓生成原理为基础,对比斜齿轮一般建模方法,从前齿廓截面、后齿廓截面的建立和螺旋线生成三个方面,提出了精确的角变位斜齿轮参数化建模方法,实现了角变位斜齿轮精确建模设计。     

基于ANSYS的多股螺旋弹簧有限元分析

简单分析多股螺旋弹簧的基本特性。以三股钢丝的多股螺旋弹簧为例,通过有限单元与接触单元的选取和网格的划分,建立多股螺旋弹簧有限元模型。然后对其进行静态受力分析和动态分析计算,分析冲击载荷质量和速度对多股螺旋弹簧性能的影响。结果表明多股螺旋弹簧在动态系统中具有内部振动波,并可能在中间产生并圈现象,为多股螺旋弹簧设计提供了依据。