构建精确的三维渐开线直齿圆柱齿轮的方法

基于CAXA制造工程师软件平台,根据渐开线的参数方程及渐开线直齿圆柱齿轮的形成原理,通过建立精确的渐开线齿轮的齿廓,实现渐开线直齿圆柱齿轮的三维精确造型。该方法为渐开线直齿圆柱齿轮的设计、分析及加工制造提供了依据。     

渐开线圆柱齿轮齿廓偏差的分析与检测

积极采用齿轮国际标准,采用先进的加工工艺,如精滚工艺、修磨齿形及改变刀具材料实现硬齿面剃齿等,使齿轮制造质量批量、稳定地达到标准要求,是我国重要的技术经济政策。新近颁布的GB／T 10095．1—2001《渐开线圆柱齿轮 精度 第1部分     

直齿圆柱齿轮热挤压工艺

采用热挤压精密成型技术，成功地研制出直齿圆柱齿轮零件，实验证明，新工艺具有优质、高效、节材、节能的特点，非常适合直齿圆柱齿轮特别是大模数齿轮的精密成型，精巧的模具设计是新工艺成功的关键。     

铣削鼓形直齿圆柱齿轮的夹具

我公司在400t滚轮架设备维修时,需经常更换鼓形齿联轴器(见图1),因没有专用滚齿机,以往鼓形齿都按直齿加工,影响质量及使用寿命。后来我们根据鼓形齿的切削原理,利用回转工作台的回转运动(进给运动)和分度头的分齿运动,在立式铣床上加工出齿轮联轴器上的鼓形齿,收到了良好的效果。     

奇数齿直齿圆柱齿轮齿顶圆直径的测量和计算

一、前言 在机械维修工作中,经常遇到奇数齿直齿圆柱齿轮齿顶圆直径的测量问题。在测量时,因为量具直接测量到的尺寸不是齿顶圆直径d_a,而是一个齿的齿顶到对面齿间齿顶圆弦的距离H(图1)。通常齿顶圆直径d_a按下式计算: d_a=KH (1) 系数K值可从有关资料中查得。 用这种方法计算齿顶圆直径,当齿数较少时,误差较大,不能满足工作要求,而对于变位齿轮、短齿齿轮、     

大直齿圆柱齿轮几何中心确定方法及齿廓偏差计算

大齿轮几何中心的确定是大齿轮测量中的重要问题。在建立渐开线齿轮离散数据模型的基础上,提出一种确定大直齿圆柱齿轮几何中心的方法,建立了相应的数学模型;根据所求出的齿轮中心,计算齿廓偏差,并与齿轮几何中心理论坐标值下计算得到的齿廓偏差进行了比较。仿真结果表明,对于加入幅值为0~318μm随机噪声后的大齿轮,计算得到的齿轮几何中心最大误差不大于1μm,齿廓偏差与理论值之间的差值不大于10μm,说明该方法可有效应用于大直齿圆柱齿轮的测量。     

用盘形铣刀铣削直齿圆柱齿轮

齿轮的加工方法很多,可分为展成法和仿形法两大类。展成法是利用刀具和工件相对运动来切削齿形的方法(图1)。仿形法则利用与齿形曲线相同的成形铣刀来加工齿形(如图2)。     

单级直齿圆柱齿轮减速器可靠性优化设计

建立了单级直齿圆柱子齿轮减速器可靠性优化设计数学模型，并采用非线性离合复合形的优化方法，进行了可靠性优化设计计算，取得了满足可靠性要求的优化结果。     

直齿圆柱齿轮二维平面图的快速绘制

在Auto CAD平台上，以Visual Lisp为开发工具，开发了标准直齿圆柱齿轮的参数化绘图程序，可快速地绘制齿轮的剖视图和轮毂键槽的端面图，有较好的使用价值。     

Experimental measurement of gear mesh stiffness of cracked spur gear by strain gauge technique

In this paper, an experimental technique based on strain gauge has been proposed to measure the gear mesh stiffness of healthy spur gear as well as of cracked spur gear pair system. Calculation of mesh stiffness of healthy and cracked spur gear tooth are based on strain energy and strain energy release rate respectively. The location of strain gauge plays an important role in calculation of strain energy stored in gear tooth. The locations of strain gauge on gear tooth are illustrated for healthy and cracked gear. Stress intensity factor (SIF) has been calculated by strain gauge technique for calculating the stiffness of cracked pinion tooth. The effect of crack length on mesh stiffness has been investigated by strain gauge technique and results are compared with the established analytical method.     

Study of a spur gear dynamic behavior in transient regime

In this paper the dynamic behavior of a single stage spur gear reducer in transient regime is studied. Dynamic response of the single stage spur gear reducer is investigated at different rotating velocities.First, gear excitation is induced by the motor torque and load variation in addition to the fluctuation of meshing stiffness due to the variation of input rotational speed. Then, the dynamic response is computed using the Newmark method. After that, a parameter study is made on spur gear powered in the first place by an electric motor and in the second place by four strokes four cylinders diesel engine. Dynamic responses come to confirm a significant influence of the transient regime on the dynamic behavior of a gear set, particularly in the case of engine acyclism condition.     

A study of spur gear pitting formation and life prediction

In this study, a numerical prediction on pitting formation is carried out in spur gear made from austempered ductile iron. General two-dimensional rolling sliding contact situations are considered for the development of the analytical model. The problem is assumed under linear elastic fracture mechanics and the finite element method is used for numerical solutions. Mixed mode stress intensity factors K_I and K_II for cyclic loading are evaluated and related to crack extension by a Paris-type equation. The maximum tangential stress criterion is used to determine the crack-turn-angle during crack propagation under cyclic loading.A series of experimental study is also carried out to determine the pitting formation life. Test specimens were first austenitized in salt bath at 900 °C for 90 min after which they were quenched in salt bath at 325 and 425 °C, for 60 min. A comparison is carried out between numerical and experimental results.     

The influence of operating condition on acoustic emission (AE) generation during meshing of helical and spur gear

The application of high-frequency acoustic emission (AE) technology to condition monitoring of gears is still in its infancy. Understanding the influence of gear operating parameters on the generation of AE is essential in applying the AE technology to gear condition monitoring. This paper presents experimental findings on the influence of speed and load in generating AE for operating helical and spur gears. The experimental findings suggest that any percentage reduction in specific film thickness (λ), a direct consequence of a change in load condition, results in a nine- and four-fold percentage change in AE rms for the spur and helical gear sets, respectively. A numerical model representing changes in AE rms with variation in load and speed under near isothermal conditions for spur and helical gears was also established. In conclusion, it is postulated that the AE technology could offer a means of measuring in situ the effectiveness of a lubricant for operational spur and helical gears thereby establishing if the correct lubricating conditions are present to ensure optimal life usage.     

A study on precision forging of spur gear forms and spline by the upper bound method

Precision forging is an important manufacturing procedure of spline and spur gear forms. It has advantages of improved strength, good tolerance, saving billet material, dispensing with the cutting, etc. In this paper, a mathematical model using an upper bound method is proposed for forging of spur gear forms and spline to investigate the plastic deformation behavior of billet within the die cavity. The material of solid billet was assumed as rigid–plastic and the shape of the tooth profile was accounted for the mathematical modeling of the kinematically admissible velocity field assumed for the plastic zone. The non-uniform velocity was employed for simulating the inhomogeneous deformation and the effect of barreling during the forging. Using the present model, various effects of forming parameter such as the friction factor, reduction, number of teeth, etc. upon the non-dimensional forging pressure, forging force and barreling of the spur gear forms and spline were analyzed systematically and the results compared with those of other researcher's analytical and experimental work. It is shown that the present modeling of the process improves knowledge of the process design performance for the precision forging of spur gear form and spline.     

Shape heading of splines and solid spur gear forms:: an analysis and some experiments

To analyse the process of near-net shape heading of splines and solid spur gear forms with the 15 actual involute teeth, each with a pressure angle of , where in each case these were to be forged integral with the shaft and one end of the initial deforming cylindrical specimen was considered as constrained. Two types of theoretical approaches, i.e. the upper-bound technique (Chitkara and Bhutta. Proceedings of 28 MT DR Conference, 1990. p. 431–42; Chitkara and Bhutta. International Journal of Mechanical Sciences 1995;37(12):1247–68; 1996;38(8–9):891–916) and the slab method of analysis (Chitkara and Bhutta. International Journal of Mechanical Sciences 1996;38(8–9):871–89) employed earlier for simple forging of the product were suitably modified to account for the constraint, were applied. In each case, the estimated theoretical results for the die loads at increasing die movements were compared with those observed experimentally during the quasi-static incremental heading of splines and solid spur gears using tellurium lead as the model material for the specimens. The characteristic deformation modes and some salient observations made on the working pressures during the heading process vis-à-vis simple forging of these products are given and the results are commented upon.     

Transient EHL analysis on spur gear teeth with consideration of gear kinematics

Transient 3-dimensional elasto-hydrodynamic lubrication (EHL) analysis is performed on the contacting teeth surfaces of involute spur gears. Kinematics of the gear and the pinion are taken into account to get accurate geometric clearance around the EHL region of the contacting teeth. The surface pressure and film thickness distribution for the whole contact faces in a lubricated condition at several time steps are obtained through the analysis. Besides the pressure spike at the outlet region, a representative phenomenon in EHL regime, the pressure at the inlet region is slightly higher than that of the center region. The film thickness of transient condition is thicker than that of steady condition.     

Geometric design of involute spur gear drives with symmetric and asymmetric teeth using the Realized Potential Method

The index gear drive potential is defined for the estimation of the quality of spur gear drives as a maximum contact ratio obtained at the contact of teeth profiles along the full line of action. In this paper, a new method is proposed for the geometric design of symmetric and asymmetric involute meshing in which the contact ratio of the gear drive is equal to its potential. This method is appropriate for the geometric design of spur gears with a small teeth number and is based on the generalized model of involute meshing. The gear drive potential is assigned as an input value, from which, after appropriate calculations, the geometry of rack-cutters, gears and involute meshing can be determined. Using the proposed method, the areas of the realized potential and the areas of the existence of involute gear drives are defined. In addition, many numerical examples are solved. In the cases of symmetric and asymmetric meshing, the minimum teeth number is obtained when the gear drive potential is larger than one.     

圆柱齿轮齿侧间隙自动补偿新方法的研究

在伺服驱动系统的齿轮传动机构中，为了保证双向传动精度，必须采取措施消除齿侧间隙。本文给出了一种采用滑动销移动错齿消除齿侧间隙的新方法，论述了新方法结构设计中部分参数的相互关系及取值范围。该结构简单，承载能力强，齿侧间隙可自动补偿。     

Undercutting and contact characteristics of longitudinal cycloidal spur gears generated by the dual face-hobbing method

This paper investigated the undercutting of longitudinal cycloidal spur gear generated by the dual face-hobbing method. Sensitivity of transmission errors and contact patterns due to varied assembly errors were studied using the tooth contact analysis (TCA) technique. The undercut of the longitudinal cycloidal spur gear is similar to the regular spur gear except for the fact that the helical angle is varied along the longitudinal direction due to the cycloidal cutting trace. Several numerical examples are presented to validate the derived undercutting of the proposed longitudinal cycloidal spur gear and the tooth contact pattern sensitivity. As expected, the bearing contact and transmission error are insensitive to the assembly error.