辛普森行星齿轮机构虚拟装配及运动分析

介绍了利用Pro/E软件对辛普森行星齿轮机构进行虚拟装配的方法和步骤,以及采用Pro/Mechanism进行运动学仿真的过程,同时详细的分析了辛普森齿轮机构在各个档位的工作情况;通过对输入、输出转速的测定,能够计算出传动比,与理论值完全吻合,表明可以利用虚拟装配技术分析复杂行星齿轮机构.     

德国伊萨切割机的故障分析和维修技巧

数控切割机是机械工业中常见的设备,数控机床是一种高科技含量、高精度要求,专门用于加工复杂曲面零件的机床,这种机床的数控系统对一个国家的航空、航天、军事、科研、精密器械、高精医疗设备等行业,有着举足轻重的影响力.     

螺旋锥齿轮副大轮齿顶线倒角加工方法研究

基于螺旋锥齿轮副中大轮采用的半滚切法加工原理,提出了一种螺旋锥齿轮副大轮齿顶线倒角加工方法,阐述了齿顶线倒角加工的原理。建立了倒角加工数学模型,通过对倒角刀具的运动分析,得出了倒角刀具运动的轨迹方程,并把倒角轨迹问题的求解归结为一个约束优化问题,应用MATLAB商用软件进行优化求解,以获得最佳的设计变量,即刀具旋转中心在刀具平面中的位置坐标和刀具半径。通过实例仿真,验证了理论方法的有效性,对工程应用有一定参考价值。     

弧齿线圆柱齿轮全修形齿面的CNC修形加工方法

针对弧齿线圆柱齿轮全修形齿面的修形控制问题,提出一种在展成加工的同时对齿廓和齿线两个方向进行修形控制的加工方法。通过调整直刃刀盘的展成运动回转半径,实现齿面齿廓方向的修形量控制;通过调整刀倾角,实现齿面齿线方向的修形量控制。基于空间运动学原理,利用矢量旋转公式,在具有倾角的数控机床上与普通多轴联动数控机床上展成加工齿面时,保持刀具和工件的相对位置和相对运动相同,进行两类机床之间的运动转换,建立机床运动控制方程,从而实现弧齿线圆柱齿轮在普通多轴联动数控机床上的修形加工。并通过试件的切削试验和齿面接触分析试验,证明所提出的修形加工方法和分析的加工运动方程的正确性。与弧齿线圆柱齿轮传统的加工方法相比,这种加工方法效率高,运动关系简单,便于推广应用。     

第一类齿轮集机构复合齿轮最小层数证明

抗干涉齿轮集（CMG）机构是一种复杂的密码鉴别机构,可用于确保要害系统保证性的机械组合锁中。CMG机构的密码鉴别功能取决于由多层密码齿轮堆叠而成的2个复合齿轮。在满足同样的密码鉴别功能的前提下,复合齿轮层数的最小化有利于应用CMG机构的机械组合锁的小型化、可靠性和制造性。复合齿轮最小层数的问题是CMG机构最重要的基本问题之一,迄今为止却未见相关报道。介绍了证明过程中所需要的基本概念,包括CMG机构的密码鉴别原理、CMG机构编码问题的定义和CMG机构优化编码的分层判据;证明了第一类CMG机构的复合齿轮的最小层数为3,也解释了此前报道的“3色循环着色编码方法”原理;当解锁符号序列仅有1次“AB”或“BA”的跳变时,第一类CMG机构存在一种退化特例,其复合齿轮齿的最小层数为2,由于退化特例不具有实用性,在工程应用中可以忽略。     

Torque loss in a gearbox lubricated with wind turbine gear oils

In this study, four different fully formulated ISO VG 320 wind turbine gear oils were select: a mineral oil‐based, a polyalphaolefin‐based, an ester‐based and a polyalkyleneglycol‐based fluids. Their physical properties (viscosity, thermoviscosity, piezoviscosity etc.) were characterised for a wide range of operating temperatures. A two‐stage multiplying gearbox, with helical gears, was selected to evaluate the influence of the wind turbine gear oil formulation on torque loss with the gearbox operating at low speed (130–230 rpm) and high torque (500–1000 Nm). The results obtained showed that each wind turbine gear oil formulation generated very different torque losses, evacuated heat flows and operating temperatures, with differences above 20 °C under the most severe operating conditions. A numerical model was developed, simulating all power loss mechanisms inside the gearbox, in particular the churning and friction losses. The coefficients of friction, between gear teeth and between rolling elements and bearing raceways, were calculated for all the tested oils. Copyright © 2013 John Wiley & Sons, Ltd.     

螺旋锥齿轮螺旋变性半展成法数控加工研究

螺旋锥齿轮齿面接触区的形状、大小和位置,对齿轮的平稳运转、使用寿命和噪声具有直接影响。针对齿轮副接触情况,利用数控铣齿机调整的灵活性,将螺旋运动应用于螺旋锥齿轮的小轮加工过程,在啮合原理和产形轮原理的基础上,提出了螺旋变性半展成法,研究了螺旋变性半展成法的加工原理和切齿方法,建立了螺旋锥齿轮副的切齿模型和数字化加工模型,给出了机床调整关系式。齿面接触分析(TCA)结果表明:使用螺旋变性半展成法加工螺旋锥齿轮副可以从本质上避免接触区呈对角接触的现象,降低了调整修正过程的复杂程度。     

新型正弦行星齿轮流量计的三维实现及流量脉动分析

根据正弦函数曲线类比推导出了正弦齿轮的直角坐标方程,利用CAXA电子图板2007的公式曲线功能和Pro/E软件建立了正弦齿轮和流量计的三维模型。为了探究正弦行星齿轮流量计的测量精确性,进行了流量脉动分析,分析结果表明:该流量计比渐开线齿轮流量计具有更小的流量脉动率。     

Reverse engineering of machine-tool settings with modified roll for spiral bevel pinions

Although a great deal of research has been dedicated to the synthesis of spiral bevel gears, little related to reverse engineering can be found. An approach is proposed to reverse the machine-tool settings of the pinion of a spiral bevel gear drive on the basis of the blank and tooth surface data obtained by a coordinate measuring machine(CMM). Real tooth contact analysis(RTCA) is performed to preliminary ascertain the contact pattern, the motion curve, as well as the position of the mean contact point. And then the tangent to the contact path and the motion curve are interpolated in the sense of the least square method to extract the initial values of the bias angle and the higher order coefficients(HOC) in modified roll motion. A trial tooth surface is generated by machine-tool settings derived from the local synthesis relating to the initial meshing performances and modified roll motion. An optimization objective is formed which equals the tooth surface deviation between the real tooth surface and the trial tooth surface. The design variables are the parameters describing the meshing performances at the mean contact point in addition to the HOC. When the objective is optimized within an arbitrarily given convergence tolerance, the machine-tool settings together with the HOC are obtained. The proposed approach is verified by a spiral bevel pinion used in the accessory gear box of an aviation engine. The trial tooth surfaces approach to the real tooth surface on the whole in the example. The results show that the convergent tooth surface deviation for the concave side on the average is less than 0.5 μm, and is less than 1.3 μm for the convex side. The biggest tooth surface deviation is 6.7 μm which is located at the corner of the grid on the convex side. Those nodes with relative bigger tooth surface deviations are all located at the boundary of the grid. An approach is proposed to figure out the machine-tool settings of a spiral bevel pinion by way of reverse engineering without having known the theoretical     

齿轮轮缘厚度对裂纹扩展路径的影响研究

齿轮是机械传动中非常重要的零部件之一.随着我国直升机传动系统的发展,对齿轮传动的可靠性提出了更高的要求.齿轮在传动过程中经常发生齿根疲劳折断现象,严重影响了齿轮的传动.因此,从线弹性断裂力学角度出发,提出了基于Abaqus的计算齿轮断裂过程中断裂参数的方法,并分步模拟了裂纹的扩展趋势,同时比较在全齿高不变的情况下,齿轮上不同的轮缘尺寸对裂纹扩展路径以及裂纹扩展速率的影响,为齿轮传动的安全性和可靠性设计打下基础.