数控车床加工仿真的一种改进方法

根据车削加工的特点,研究了数控车床加工过程的三维仿真问题.提出了一种新的基于刀具轨迹斜率变化量的工件离散化和特征点筛选方法,与传统三维仿真方法相比,大大减少了工件建模所需的特征点数,提高了计算速度.文末通过算例证明了所提出方法的有效性.     

函数方程曲线的数控加工

介绍了两种函数方程曲线加工方法。一种是直接在加工中心系统上,利用函数运算功能边计算边加工。另一种是在CAD中根据所给的函数方程画出图形,在CAM中生成刀具轨迹程序进行加工。     

浅谈活塞加工专用数控机床

通过对活塞的外圆面进行数学建模,使其曲面网格化,编制活塞加工专用软件。为了提高精度及效率,应用静压主轴单元及全闭环高频响伺服系统进行控制。     

智能小型(活塞)几何尺寸自动分选机的研制

本文介绍了研制成功、行之有效的小型(活塞)几何尺寸自动分选机的工作原理、性能与微机数据处理及控制和自动分选。     

基于小波变换的柱塞泵故障诊断方法

基于柱塞泵的脉动分析模型,提出了一种基于小波变换的柱塞泵故障诊断方法。以泵出口处的压力信号作 为分析信号,利用小波变换将该信号进行频谱分解,可有效地提取压力信号中所包含的故障信号。仿真与试验结 果均表明:基于小波变换对泵出口压力信号的分析可实现泵的故障诊断。     

超硬刀具在铝合金活塞加工中的应用与发展

超硬刀具是实现高效高速加工的关键,介绍了超硬刀具的性能特点,回顾了超硬刀具在活塞加工中的应用推广情况,分析了超硬刀具在活塞加工中存在的各种问题及其原因,对超硬刀具在活塞加工的前景进行了展望,并对超硬刀具的应用推广提出了建议。     

准双曲面齿轮加工调整计算新方法

准双曲面齿轮是齿轮传动中最复杂的，其工艺锥参数和加工调整计算都涉及两个相错圆锥的相切接触条件。现有文献都从空间立体几何用图形分析，涉及变量多，方程组求解困难。根据相切接触条件用纯解析的方法，易理解，计算简单。     

卧式加工中心几何精度立体检验的研究

根据卧式加工中心加工零件时影响加工精度的误差实情，建立起机床立方体工作区精度系统。提出分别以镗孔精度、铣沟槽精度和轮廓加工精度表征卧式加工中心工作精度的概念，从而解决了检出的机床几何精度与被加工零件的相应型面精度之间无直接对应关系的难题。用于实践，取得了良好效果。     

Friction model of a marine diesel engine piston assembly

In modern marine diesel engines, power output and in-cylinder firing pressures are constantly increasing, leading to higher friction in engine components and especially in the piston assembly. A good understanding of the friction contributions of the various engine components is needed, if mechanical efficiency is to be improved. A friction model for the engine piston assembly has been developed and is presented in this paper. The model, based on lubrication theory, considers the detailed engine geometry and the complete lubricant action, and thus can be applied to a wide range of engines. In detail, the analysis takes into account the friction components of compression rings, oil control rings, piston skirt and gudgeon pin of the engine piston assembly. The model was applied to a four-stroke (medium speed) marine diesel engine and the effect of engine speed and load on friction was examined and compared with results from other semi-empirical models. The engine friction was predicted at constant rotational speed (generator operation) and variable rotational speed (propulsion operation).     

加工变椭圆活塞工装设备的设计及应用

为了解决中小企业加工变椭圆活塞既要节省设备投资,又要保证加工精度的实际问题,介绍了一种在现有车床上使用专用工装设备加工变椭圆的活塞的加工方法及工艺装备的设计.通过实际使用证明,此工装设计合理,能保证活塞加工精度及要求.     

一种数控加工中心工艺文件编制方法

分析数控加工中心工艺的特点及改进传统工艺编制方法的必要性。介绍一种适合数控加工中心特点的零件加工工艺的编制方法。     

Implementation of the principal-axis method for machining of complex surfaces

In this paper a new strategy for 5-axis machining of complex surfaces is presented. The method uses curvature alignment and matching between the design surface and the cutting tool to improve surface finish and reduce machining time. The method is implemented on two configurations of 5-axis machines, and used to machine a test surface. The results of the tests show a considerable improvement over conventional 3-axis machining.     

On the instantaneous and average piston friction of swash plate type hydraulic axial piston machines

Piston friction is one of the important but complicated sources of energy loss of a hydraulic axial piston machine. In this paper, two formulas are derived for estimating instantaneous piston friction force and average piston friction moment loss. The derived formula can be applicable for piston guides with or without bushing as well as for axial piston machines of motoring and pumping operations. Through the formula derivation, a typical curve shape of friction force found from several experimental measurements during one revolution of a machine is clearly explained in this paper that it is mainly due to the equivalent friction coefficient dependent on its angular position. Stribeck curve effect can easily be incorporated into the formula by replacing outer and inner friction coefficients at both edges of a piston with the coefficient given by Manring (1999) considering mixed/boundary lubrication effects. Novel feature of the derived formula is that it is represented only by physical dimensions of a machine, hence it allows to estimate the piston friction force and loss moment of a machine without hardworking experimental test.     

一种加工长锥度的新方法

介绍了一种加工长锥度的方法,成功突破了锥面加工长度受小拖板长度限制的要求。     

基于啮合角函数的平面圆齿轮共轭齿廓求解及几何特性研究

定义了啮合角函数,由此,建立了共轭齿廓方程,并导出齿廓曲率半径、齿廓弧长和滑动系数计算公式;提出了齿廓根切和啮合界限点的条件。啮合角函数决定了齿廓形状及几何特性,无需坐标系间的旋转变换,可直接由啮合角函数求解共轭齿廓;无需先给定齿廓曲线,即可由啮合角函数系统地对齿廓几何特性进行分析。该共轭齿廓的直接求解及几何特性研究甚为简便。     

一种加工超长内、外锥度的靠模

从设计结构、加工方法、机床改造角度 ,介绍一种加工超长内、外锥度靠模的方法     

旧机床数控化再制造案例研究

从再制造和绿色度的概念出发,介绍了机床数控化再制造的一般方法。详细阐述了C5225立式车床数控化再制造的方案,包括采用电主轴、更换电动刀架、选配数控系统、实现半闭环伺服驱动等。对案例进行了技术可行性分析,得出了数控化再制造可行的结论。     

Experimental study of wear interaction between piston ring and piston groove in a radial piston hydraulic motor

The wear interaction between piston ring and piston groove in a radial piston hydraulic motor was studied in regard to mass loss and changes in form and surface roughness. A specially developed test rig that simulates the tilting movements of pistons at the end of strokes was used in the test. The results show that wear on the piston ring groove can be up to 10 times greater than the wear on the piston ring. For both interacting surfaces, the dominant wear mechanism was mild wear. The results from a factorial design show that the form of the piston groove significantly influences the amount of wear.     

车铣复合加工中心的Y轴实现形式及加工对象

分析、总结了国内外车铣复合加工中心的差距,介绍了车铣复合加工中心的Y轴实现形式和加工对象.     

活塞环加工与新型数控车床方案研究

从活塞环自由状态轮廓型线出发，分析了活塞环内外圆切削加工对设备的要求，讨论了现有各类活塞环内外圆切削加工设备的特点和存在的不足，介绍了笔者正在研制的新型活塞环全数控加工设备的工作原理和结构方案。