超声研齿换能器的设计与研齿试验

介绍了超声研齿的原理与方法,并将超声加工应用于齿轮研磨。利用力电类比和四端网络法,构建超声研齿换能器的等效网络图,通过电路运算,得到了换能器的频率方程与前后端面振速比的计算公式。据此设计了谐振特性良好的1/2波长超声换能器。进行了超声研齿与普通研齿对比试验,利用扫描电镜(SEM)图像分析了两者的材料去除机理。试验表明超声研齿材料去除率可达到普通研磨的3倍,且齿面质量明显提高,齿面粗糙度Ra低至0.2mm,水平截距c减小到1.2!m。     

球磨机筒体和大齿圈的安装调整方法

文章介绍了永平铜矿φ5.03×6.4m球磨机大修中筒体翻转及筒体和大齿圈的安装调整方法.为同类设备的检修提供可借鉴的经验.     

人字齿轮直线型对角修形设计及成形磨原理

为了降低承载传动误差波动产生的振动激励，提出了成形磨人字齿轮直线型对角修形优化设计。根据ISO对角修形定义，计算齿顶、齿根修形起始线在旋转投影面上的螺旋角，将修形曲线设计为直线型，给定最大修形量，确定对角修形的齿面方程。利用齿面接触分析和轮齿承载接触分析，以工作载荷下人字齿轮承载传动误差波动量最小为优化目标，采用遗传算法优化对角修形参数。确定以目标修形齿面法向偏差的平方和最小的目标函数，以螺旋角、模数、压力角为设计变量，采用遗传算法分别对齿顶和齿根修形区域进行逼近，从而实现对角修形的成形磨加工。结果表明，人字齿轮直线型对角修形可以将承载传动误差波动量降低到36.65%；采用三截面砂轮成形磨的理论误差控制在1μm以内，获得较高的齿面精度；试验人字齿小轮齿的检测结果控制在4级精度以内，并进行了齿轮副的滚检试验，从而验证该方法的有效性。     

Effect of temperature on the scuffing load capacity of EP gear lubricants

Scuffing of gears involves the welding together of locally unprotected metal‐to‐metal contacts when critical limits of pressure and temperature are exceeded. Protection can be maintained by a thick lubricant film, by physically adsorbed layers, or by chemical reaction layers. At higher temperatures, viscosity and film thickness decrease but, using an EP gear oil, due to higher chemical reactivity, the scuffing load capacity is not necessarily reduced accordingly. The reaction temperature of the additives is not always reached for large gears. In this paper the factors that influence the scuffing load capacity are investigated, and test possibilities and calculation methods are outlined.