单一斜齿圆柱齿轮精确测量的简便方法

从制造的角度出发,阐述了精确测量单一斜齿圆柱齿轮齿形参数的简便方法,测量公法线长度计算基圆齿距从而查表确定模数和压力角,测齿顶圆直径估算分度圆螺旋角,用滚齿机修正分度圆螺旋角,并以实例说明测算的步骤,结果表明,该法避开了与加工无关的参数的反复测算,且测绘的精度能满足使用的要求。     

Forced vibration of composite cylindrical helical rods

The dynamic behavior of composite cylindrical helical rods subjected to time-dependent loads is theoretically investigated in the Laplace domain. The governing equations for naturally twisted and curved spatial laminated rods obtained using Timoshenko beam theory are rewritten for cylindrical helical rods. The curvature of the rod axis, the anisotropy of the rod material, effect of the rotary inertia, axial and shear deformations are considered in the formulations. The material of the rod is assumed to be homogeneous, linear elastic and anisotropic. Ordinary differential equations in scalar form obtained in the Laplace domain are solved numerically using the complementary functions method to calculate the dynamic stiffness matrix of the problem accurately. The solutions obtained are transformed to the time domain using an appropriate numerical inverse Laplace transform method. The free vibration is then taken into account as a special case of forced vibration. The results obtained in this study are found to be in a good agreement with those available in the literature.     

Simple apparatus for measuring the dynamic shear modulus of cylindrical specimens

An apparatus is decribed which has been used to determine the shear modulus of cylindrical specimens vibrating in the torsional mode. The specimens are maintained in self-excited vibration by an eddy-current driver, an eddy-current pickup, and a feed back circuit consisting of a phase-locked-loop and an amplitude control module. The system has a frequency stability of 1 part in 10(6) for high-Q materials (a few thousand) in the audio range. In addition, it can automatically track frequency changes of a few percent with negligible error in phase or frequency.     

利用UG对渐开线斜齿圆柱齿轮参数化设计

渐开线斜齿圆柱齿轮是机械传动中常用零件,由于齿形轮廓复杂,其参数化设计困难.利用三维软件UG-NX3对斜齿圆柱齿轮进行三维建模,首先利用"模型"模块中的规律曲线、扫描、缝合、休整和抽取等运算,建立齿槽轮廓,经布尔运算形成齿槽轮廓体,对其特征阵列,生成斜齿圆柱齿轮三维模型.同时以齿数41为界,对两种齿轮建模方法不同之处进行介绍.该方法实现了改变斜齿圆柱齿轮的齿数、法向模数和螺旋角等参数,立即得到相应的渐开线斜齿圆柱齿轮三维模型的参数化设计.对其他具有复杂表面形状的形体参数化设计具有参考价值.     

圆柱螺旋扭转弹簧的模糊可靠优化设计

在弹簧的一般优化设计的基础上,根据模糊可靠设计准则,考虑各参数取值的不确定性,建立了圆柱螺旋扭转弹簧模糊可靠优化设计的数学模型,并对其进行计算分析。     

An efficient numerical method for predicting the natural frequencies of cylindrical helical springs

In this study, the stiffness method is employed for the free vibration problem of cylindrical helical springs. The element stiffness matrix for the helical spring with twelve degrees-of-freedom is obtained exactly by the transfer matrix method. The efficacious numerical algorithm is employed for the computation of the element transfer matrix. The concentrated element mass matrix is used. The subspace iteration method is preferred for the solution of the large-scale eigenvalue problem. The axial and shear deformation and the rotary inertia terms are considered in the formulation. The free vibrational parameters are chosen as the number of coils (n=3–16), the helix pitch angle (α=5–25°), the shape of cross-section (circular, hollow circle and squared) and as the ratio of the diameters of cylinder to wire (D/d=4–16) in a wide range. Solving the miscellaneous problems, the non-dimensional charts are obtained for the cylindrical helical springs fixed at both ends. Using these charts the natural frequencies are expressed in analytical form in a very good approximation (with the maximum absolute relative error of 5%) and presented for the designers.     

预应力圆柱螺旋弹簧弯曲弹性特性研究

研究了预应力圆柱螺旋弹簧的弯曲弹性变形特性.通过对弹簧圈进行受力分析,利用材料力学的相关理论,推导了弹簧在受到弯矩作用时弯矩与弯曲角度之间的关系,得出了弹簧弯曲角度的计算公式,并对参数进行了优化.通过试验验证,表明所提出的公式精度较高,能满足工程设计的需要,为后续弹簧系统的动力学性能研究奠定了基础,同时也为新弹簧的设计提供了一定的理论依据.     

二级斜齿圆柱齿轮减速器的多目标优化设计

通过对二级斜齿圆柱齿轮减速器系统的传动情况设计了一套优化方案,建立了多目标优化方法,根据应用值得实际参数确定了约束条件,对系统进行了优化,对该齿轮传动系统在设计上提供了较新的解决办法。     

斜齿圆柱齿轮在UG中的三维建模

阐述了利用UG软件的建模功能，生成一渐开线斜齿圆柱齿轮，包括渐开线公式在UG中的表达式建立方法及应用自由曲面造型中扫描方式进行轮齿部分的造型。给出渐开线斜齿圆柱齿轮一个完整模型。     

Linear free vibration analysis of cross-ply laminated cylindrical helical springs

A linear free vibration analysis of symmetric cross-ply laminated cylindrical helical springs is performed based on the first-order shear deformation theory. Considering the rotary inertia, the shear and axial deformation effects, governing equations of symmetric laminated helical springs made of a linear, homogeneous, and orthotropic material are presented in a straightforward manner based on the classical beam theory. The free vibration equations consisting of 12 scalar ordinary differential equations are solved by the transfer matrix method. The overall transfer matrix of the helix is computed up to any desired accuracy. The soundness of the present results are verified with the reported values which were obtained theoretically and experimentally. After presenting the non-dimensional graphical forms of the free vibrational characteristics of (0°/90°/90°/0°) laminated helical spring made of graphite-epoxy material (AS4/3501-6) with fixed–fixed ends, a non-dimensional parametric study is worked out to examine the effects of the number of active turns, the shear modulus in the 1–2 plane (G₁₂), the ratio of the cylinder diameter to the thickness (D/d), and Young's moduli ratio in 1 and 2 directions (E₁/E₂) on the first six natural frequencies of a uniaxial composite helical spring with clamped-free, clamped-simple, and clamped–clamped ends.     

Modifying the teeth of cylindrical helical transmissions to reduce vibration

Low noise and vibration are required of gear transmissions. Appropriate modification of the lateral tooth surfaces in helical (chevron) cylindrical transmissions significantly reduces the vibration excited by the variable coupling rigidity and discrete (abrupt) tooth loading.     

一种测定圆柱螺旋铣刀各阶固有频率的方法

通过引入刀杆有效截面系数的概念 ,提出一种在不同悬臂长度下确定刀具各阶固有频率的新方法。该方法对同一把铣刀 ,只需一次性测量计算 ,就可确定其在任意悬臂长度时比较精确的各阶固有频率 ,无需再去关心刀具材料特性参数和几何参数。     

基于ANSYS含齿根裂纹斜齿圆柱齿轮模态分析

采用ANSYS参数化设计语言(APDL)建立了有裂纹和无裂纹斜齿圆柱齿轮三维模型,运用有限元方法研究了不同尺寸齿根裂纹对齿轮结构固有特性的影响。结果表明:当裂纹发生时,裂纹齿轮刚度损伤较大,致使齿轮的固有频率有所降低,低阶固有频率变化梯度大于高阶固有频率变化梯度,裂纹对相应的各阶主振型影响不明显。     

基于MATLAB的二级圆柱齿轮减速器优化设计

传统减速器设计一般通过反复的试凑、校核确定设计方案,虽然也能获得满足给定条件的设计方案,但方案一般不是最佳的。在系统研究二级圆柱齿轮减速器优化设计目标、设计变量和约束条件的基础上,建立了优化设计数学模型。利用MATLAB的优化工具箱,对减速器进行优化设计,简化了复杂的编程,提高了设计效率和质量。     

非圆形截面钢丝圆柱螺旋压缩弹簧设计计算方法的探讨

本文对常见的矩形、椭圆形以及卵形截面钢丝圆柱螺旋压缩弹簧设计计算法从理论上进行了探讨,从根本上揭示了目前各类手册及国外有关资料介绍的矩形、椭圆形以及卵形设计计算公式的理论依据,并给出了设计计算公式。     

基于MATLAB的三级圆柱斜齿轮减速器可靠性优化设计

传统的减速器设计是以设计者的经验为基础的,因此设计方案往往不是最优的.为了在不影响性能的基础上实现体积和重量的最小化,本研究运用可靠性设计与优化设计相结合的方法建立了某起重机三级圆柱斜齿轮减速器的可靠性优化设计模型.利用MATLAB优化工具箱具有编程工作量少、语法符合工程设计要求等特点,以减速器箱体壁厚作为自变量.以箱体体积最小为目标函数,在约束函数中充分考虑可靠性的要求,对该减速器进行可靠性优化设计.优化结果表明,可靠性优化是一种更科学、更符合客观实际的设计方法院,而且该方法应用到工程实际中会大幅地节约成本,提经济效益.     

用双向扭转圆柱组合螺旋弹簧实现扭矩测试

利用单个圆柱螺旋扭转弹簧扭转原理,给出了一种用双向扭转圆柱组合螺旋弹簧实现扭矩测试的方法。根据扭转弹簧模型,给出了预紧力、加载的证明,并对实验结果进行分析;该结构用于扭矩测试系统既实用可靠,又简单易加工;降低了测试系统的成本,具有很高的实用价值。     

基于模糊熵理论的圆柱螺旋压缩弹簧模糊可靠性设计

模糊可靠性设计是将模糊设计理论与可靠性设计理论相结合的一种现代设计方法,但模糊设计理论中的隶属函数上、下界的确定主要依据经验性的扩增系数法,往往缺乏科学性。引入熵理论,可以在不完全依靠设计者经验的前提下对可靠性设计的模糊程度进行数值计算,定量描述隶属函数上、下界与可靠度的关系,并对圆柱螺旋压缩弹簧强度进行了模糊可靠性设计,为机械模糊可靠性设计提供了新方法。     

Evaluation of echo signals from dihedral angles in specimens with cylindrical surfaces

Formulas for an acoustic channel are obtained for an angle probe and a reflector in the form of dihedral angle, which is formed by the end and cylindrical surfaces of a specimen—a round cylinder. It has been shown that, when the wave path in a prism is much shorter than the cylinder’s radius, the decrease that occurs in the amplitude of the echo-signal from the dihedral angle (without additional repeated reflections) owing to a wave-front divergence is the same as that observed during the reflection from a plane surface. The calculated and experimental data are compared.     

平行轴斜齿轮诱导法曲率计算

基于微分几何理论,采用解析方法推导出渐开线平行轴斜齿圆柱齿轮的诱导法曲率公式,并利用Matlab编制程序对诱导法曲率进行仿真分析,研究了渐开线平行轴斜齿圆柱齿轮诱导法曲率与螺旋角、模数以及大、小齿轮齿数的关系,为科学地选择齿轮最佳参数提供了一种研究方法,具有一定的实用价值.