基于精确齿廓模型的直齿轮轮齿变形数值计算

根据齿轮加工原理及渐开线展开原理,建立了直齿轮齿廓的数学模型.用Weber能量法计算直齿轮轮齿变形,用Matlab语言编制了轮齿变形计算程序,为准确、快速求解直齿轮轮齿的变形和啮合刚度奠定了基础.     

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.     

外齿轮内平动式新型少齿差行星传动的研究

提出了一种具有实用价值的外齿轮内平动式的新型少齿差行星传动.分析了这种行星传动的传动原理、基本结构、传动比、啮合参数和传动效率.同时,提出使用功能强大的数学软件MATHCAD确定新型少齿差行星传动变位系数的CAD方法.分析表明,这种传动能够达到系统的静平衡和动平衡,具有结构紧凑、体积小、承载能力和传动效率高、制造简单等优点,是一种很有发展前景的传动形式.     

直齿圆柱齿轮表面微凸起磨损的时变热效应弹流润滑分析

以渐开线直齿圆柱齿轮为研究对象,建立考虑表面微凸起的润滑模型,给出相应的膜厚方程.在以往表面粗糙度的研究基础上,对两齿面的表面微凸起在不同磨损程度下的热解进行数值分析.结果表明:齿面上的微凸起会明显影响齿轮间的润滑效果,会对齿轮齿面造成比微点蚀更大的损伤;对于两个表面均存在微凸起的齿面,齿面的磨合磨损主要发生于主动轮上时,相比发生在从动轮上,会减缓对齿轮啮合过程中压力冲击的影响,会使油膜的中心压力、膜厚等变化趋于平缓.     

Lubricant and additive effects on spur gear fatigue life

Spur gear endurance tests were conducted with six lubricants using a single batch of consumable-electrode vacuum melted (CVM) AISI 9310 spur gears. The sixth lubricant was divided further into four batches, each of which had a different additive content. Lubricants tested with a phosphorus-type load carrying additive showed a statistically significant improvement in life over lubricants without this type of additive. The presence of sulphur-type antiwear additives in the lubricant did not appear to affect the surface fatigue life of the gears. No statistical difference in life was produced with those lubricants of different base stocks but with similar viscosity, pressure-viscosity coefficients and antiwear additives. Gears tested with a 0.1 wt % sulphur and 0.1 wt % phosphorus EP additives in the lubricant had reactive films that were 200 to 400 Å (0.8 to 1.6 μin) thick.     

Wear simulation of spur gears

This paper deals with prediction of wear in spur gears, which has been calculated using an approach in which the wear depth on a tooth surface is integrated over time using the Euler integration method. Variations in pressure distribution over the surface have been considered, as well as changes in curvature and surface profile of the teeth as they wear. The paper focuses on the use of an appropriate wear model for simulating wear using calculated conditions between high-performance slow-running lubricated spur gears. A numerical model for prediction of surface interaction of spur gears developed earlier by the authors has been applied as the basis for the simulation of wear using different wear models. Owing to the nature of the wear models, methods of calculating the contact temperature have been investigated for the specific case of interacting gear teeth. It was found that a linear wear model, when compared with a more complex oxidation model and with a model based on adsorption of lubricant molecules, satisfactorily predicts wear. It was also found that it is the geometry of the gears that causes sliding velocity to be the dominant wear-inducing factor, and so determines the general nature of the wear behaviour.     

Thermo-elastohydrodynamic lubrication of an involute gear

This paper analyses the thermo-elastohydrodynamic lubrication on an involute spur gear tooth surface and the influence of the inlet temperature of the lubricant. The oil film temperature distribution shows a minimum near the point where the pressure distribution is a maximum and the energy loss a minimum. Then the temperature increases slightly in the outlet region. Calculated results show a decrease of a few percent in the maximum pressure distribution compared with an oil film on a rigid surface. Based on oil film thickness and gear tooth deflection, the load sharing coefficient and the relative transmitting errors are calculated. The behaviour of the oil film due to the variation of the normal tooth load at the transition point of the meshing is investigated also     

Experimental investigation of fatigue behavior of spur gear in altered tooth-sum gearing

This paper deals with the contact stress, power loss, and pitting of spur gear tooth in altered tooth-sum gearing for a tooth-sum of 100 teeth when altered by±4% tooth-sum. Analytical and experimental methods were performed to investigate and compare the altered tooth-sum gearing against the standard tooth-sum gearing. The experiments were performed using a power recirculating type test rig. The tooth loads for the experimental investigations were determined considering the surface durability of gears. A clear picture of the surface damage was obtained using a scanning electron microphotograph. The negative alteration in the tooth-sum performed better than the positive alteration in a tooth-sum operating between specified center distances.     

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.     

直齿锥齿轮齿廓修形

根据啮合刚度和噪声之间的关系,以修形减振降噪为目的,用旋转渐开线曲线对直齿锥齿轮进行齿廓修形.以减小齿轮传动误差和啮合刚度的波动大小为衡量标准,同时确保载荷变化呈平稳过渡.静态计算结果表明,直齿锥齿轮齿廓长修形具有较好的减振效果.直齿锥齿轮采用冷精锻进行齿廓修形,显著地降低了成本,这为齿轮传动系统的修形、减振、降噪和设计提供了一种新的研究方法.     

直齿圆柱齿轮精密成形挤压型腔的参数化建模方法

齿轮精密成形是直齿圆柱齿轮成形的必然趋势,但其挤压型腔的数学模型建立困难,往往导致参数不易求解和优化。笔者提出了基于齿轮挤压型腔的参数化数学建模方法,利用Bezier曲线描述挤压型腔轴向变化规律和Pro／Engineer软件对其进行几何建模,使挤压型腔CAD／CAM一体化成为可能。     

直齿圆柱齿轮的虚拟设计与分析

利用Pro/E程序本身的参数化功能实现了渐开线直齿圆柱齿轮的三维造型,同时应用其内在的Mechanica模块对建立的参数化模型进行仿真和有限元分析,从而生成应力、应变条纹图,运行结果验证了应用Pro/E软件进行虚拟设计的可行性和分析研究的正确性,并提高了设计研究的效率。     

直齿圆柱齿轮的三维建模及有限元分析

以Pro/E为开发平台,Pro/Program为开发工具,对标准直齿圆柱齿轮的参数化建模进行了详细的介绍.只要按提示输入标准直齿圆柱齿轮的5个基本参数,就可以得到精确的直齿齿轮的三维实体.同时利用ANSYS有限元分析软件的特点,可以在不脱离Pro/E和ANSYS这两个软件的情况下对直齿圆柱齿轮进行有限元分析.     

基于AutoCAD的直齿轮齿廓的参数化设计

分析了齿轮啮合的基本原理和共轭齿形的形成及其求法,详细探讨了圆柱直齿轮齿廓模型特点,以渐开线齿条滚刀加工圆柱直齿轮为例说明齿廓的形成过程,建立了相应的数学模型.并对该模型进行了仿真,简要介绍了仿真平台的特点和功能结构,并通过该软件精确仿真出了齿轮的齿廓的曲线,符合设计要求.     

少齿数齿轮传动

介绍了少齿数齿轮的设计特点及少齿数齿轮的加工中的设备改造问题。     

奇数直齿齿顶圆直径的测量与计算

对奇数直齿圆柱齿轮齿顶圆直径的测量和计算方法进行了改进,提高了实际测量精度。     

摆动活齿传动内齿圈齿形加工方法研究

利用齿轮啮合原理求解出摆动活齿传动内齿圈齿形 ,以齿形上的特征点重新构造齿形样条函数 ,并在通用机床上进行加工 ,得到了合格的内齿圈齿形。该方法将复杂曲线的计算过程和加工过程有效分离 ,为制造复杂曲线零件提供了一种快速的通用的加工方法     

Calculation of sliding power loss in spur gear contacts

An engineering-level calculation model for sliding power loss in spur gear contacts is presented. Teeth contact through the line of action is modelled as a constantly changing roller contact whose radius, speed, and load can be calculated from the gear geometry under the given operating conditions. The gear mesh cycle is approximated by a large number of elastohydrodynamic contacts. A constant film thickness and a Hertzian pressure distribution are assumed in each contact. The model includes non-Newtonian lubricant behaviour together with temperature and mixed lubrication effects in contact. The numerical solver is reasonably fast in evaluating effectively the sliding power loss dependence on the essential gear and lubricant parameters. The features and behaviour trends of the calculated sliding power losses have a close similarity with published results obtained from measurements and experiment-based power loss models with mineral oil. The limiting shear stress of the lubricant is observed to have an essential role in the power loss behaviour especially at high loads.     

Contact stress calculation of undercut spur and helical gear teeth

The presence of undercut at the pinion root may affect the load sharing among couples of spur gear teeth in simultaneous contact, as well as the load distribution along the line of contact of helical gears. This occurs if the outside points of the wheel profile do not find, due to undercut, mating profile to mesh with, which is called vacuum gearing. Under these conditions, the effective contact ratio is reduced, and the critical contact points may be shifted from their locations at non-undercut profiles. In this paper, a non-uniform model of load distribution along the line of contact, obtained from the minimum elastic potential criterion, has been used combined with the Hertz equation for the calculation of the contact stress. A complete study on the critical load conditions and the value of the critical contact stress has been carried out, considering a wide range of the values of the geometrical parameters. As a result, a recommendation for pitting load capacity calculations of vacuum-gearing spur and helical gears is proposed.     

用积分法计算直齿轮轮齿的弹性变形

用积分法推导确定了由直齿轮轮齿在单位力作用下的弯曲变形、剪切变形和压缩变形所引起的于载荷作用点处沿载荷方向变形的计算公式,编制通用程序对它们进行了计算,并与用传统的分段方法求得的结果进行了比较。结果表明,只有分段段数足够多时,用分段法求得的结果才与积分法达到一致的结果。