高速响应活塞环数控车床关键技术的研究

活塞环内外圆轮廓是一种不规则的自由型线，切削加工困难，通常所用的仿形靠模车床存在加工效率低、调整周期长、易于磨损等缺陷。在分析活塞环切削加工特点的基础上，应用直线伺服电机研制开发了一台高速响应活塞环数控车床，并对该机床研制中的关键技术，如活塞环开口过渡曲线拟合、快速响应刀具进给系统研制、机床总体结构设计、活塞环CAD／CAM软件模块开发等进行了阐述。     

活塞环加工凸轮实际工作曲线的研究

通过对活塞环加工机构的分析研究，导出靠模机床滚轮中心轨迹曲线，进而推导出活塞环加工凸轮实际工作曲线，从理论上消除了凸轮设计误差。     

活塞环加工凸轮实际工作曲线的研究

通过对活塞环加工机构的分析研究，导出靠模机床滚轮中心轨迹曲线，进而推导出活塞环加工凸轮实际工作曲线，从理论上消除了凸轮设计误差。     

高精密微细切削加工机床的研制

微细切削技术的发展离不开微小型化机床设计和制造技术的发展,然而微细切削加工的高精度对微细切削机床的性能和设计提出了更高的要求。因此,针对微细切削机床设计和研制的特点,自主研发了一台微小型切削加工机床,该机床可应用于微细车削、刨削、飞切等加工方式。其设计理念是,利用大理石气浮导轨结合精密直线电机技术,提高机床的精度和加工稳定性。     

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。     

活塞环数控车床控制系统的研究

对扬州大学机电研究所开发的活塞环数控车床进行数控系统研究。该系统是由工业PC和多轴运动控制器构成两级控制,上位机负责系统界面管理等非实时性作业,下位机负责运动控制、PLC逻辑控制等实时控制任务。通过基于时基的电子靠模实现主轴旋转和径向进给直线伺服电动机的协调控制,完成各种活塞环型线的加工,具有较好的高频响应特性,满足活塞环车削对数控系统的功能要求。     

基于工艺参数响应曲面的干式铣削机床能效分析

针对干式切削加工能耗相对较高的问题,通过对数控铣床干切削加工过程的实时功率进行数据采集,采用响应曲面方法描述和分析了数控铣削加工各主要工艺参数与单位切削能耗和机床能效之间的定量关系。通过工艺参数对单位切削能耗和单位机床能耗的响应曲面及降维平面进行了分析,结果表明,增大工艺参数和材料去除率对于提升机床能效具有积极作用。此外,降低机床基础能耗占比、提高切削能耗占比,能有效提高干式切削机床能效。     

微机在靠模设计中的运用

靠模装置是附加在机床上的一种辅助设备可使机床获得补充进给运动,并与原有进给运动相结合,而合成新的进给运动,以满足被加工表面几何形状的要求。在一般情况下,靠模装置主要是用来扩大机床的工艺范围,完成复杂型面的加工。众所周知,靠模的精度直接影响加工零件的精度,这就要求我们寻求一种提高靠模型面精度的设计方法,现在最好的办法是在数控机床上加工靠模,但对于一般企业来说,没有数控机床,制造成本也太高。所以本文着重对讨论利用微机确定靠模型面,以提高靠模型面的精度。     

活塞环仿形靠模的设计

介绍了加工活塞环的靠模设计方法及开口部位的型线设计。     

车削锥螺纹机构的设计

加工批量较大的锥管螺纹零件(如图1所示)在普通车床上依靠斜度靠模机构,显然操作动作复杂、生产率低,劳动强度大。为此我们设计了一种机构,装置在普通机床上,在装夹好工件、调整好机床后,能够自动完成切削锥螺纹的工作。它具有结构简单、不破坏原机床结构性     

基于重复控制的数控系统伺服调节技术的研究

针对数控活塞环车削周期性控制的特点,应用重复控制理论对活塞环车床数控系统伺服调节技术进行了研究。以M序列信号作为输入信号,采用最小二乘法首先对数控伺服系统模型进行了系统辨识;以辨识所得到的整个闭环伺服系统模型为调节对象,进行了重复控制器的设计,构建了适合于伺服系统调节的重复控制器;以Matlab/Simulink为工具对所构建的重复控制器进行了仿真比较,系统跟随误差由原来94.2%减少到11.1%;同时在自行开发的数控系统上进行实际试验比较,系统跟随误差也由87.9%减少到24.7%。通过试验表明,基于重复控制的伺服调节技术能有效地抑制周期运动中的跟随误差。     

Geometric equation and machining method for the sidewall of a piston

Engine pistons are generally cut with a copy machine or a CNC machine. In recent years, CNC machining has become more popular due to the necessity for increased productivity and accuracy in piston machining. CL data are essential for CNC machining, and such data are usually generated from a 3D CAD model. When using a 3D CAD model, the intersection curves between the surfaces and the cross-sectional plane must be calculated, which is both time-consuming and imprecise. In this paper, a geometric equation for the sidewall of a piston is proposed as a solution to this problem. The geometry consists of an ellipse, recesses, eccentricities, and an offset. The equation for the sidewall of a piston is expressed in terms of the distance from the center. This equation makes it possible to calculate CL data very quickly, and facilitates the compensation of tracking error. A specialized four-axis CNC lathe, suitable for machining the sidewall of a piston, is also introduced. The proposed method has been tested by actual turning using this four-axis lathe. The results demonstrate the practicality of the method in the manufacturing of pistons.     

活塞环数控车床动态性能测试系统研究

通过对自主研发的活塞环数控车床在使用中出现的问题分析,提出了该设备动态测试的必要性,并对其进行了动态测试方案分析和切削动应变测试数据信号分析,为该数控机床今后的结构改进设计提供了依据。     

Microstructure and Mechanical Behavior of in Situ Primary Si/Mg_2Si Locally Reinforced Aluminum Matrix Composites Piston by Centrifugal Casting

Al-Si pistons are frequently damaged by burning piston top surface due to elevated combustion temperature, and by rubbing the first ring groove against the engine cylinder liner. To prevent piston from these damages, some technologies were invented, such as mounting high Ni cast iron ring around the first ring groove in Al alloy piston body and thermal resistant steel on piston top surface, and fabricating Al composite pistons by squeeze casting for enhancing the whole or local piston performance. In this paper, composite pistons locally reinforced with in situ primary Si and primary Mg2Si particles are fabricated by centrifugal casting. The microstructure characteristics, hardness and wear resistance of the composite piston are investigated and the motion characteristic of the in situ particles in centrifugal field is analyzed. The results of the experiments show that primary Si and Mg2Si particles mix up with each other in melt and segregate at the regions of piston top and piston ring grooves under the effect of centrifugal force. Particulate reinforced regions have a higher hardness and better wear resistance compared with the unreinforced regions and this performance increases after heat treatment. The analysis result of particle movement shows that, primary Si and primary Mg2Si particles move at approximately the same velocity in the centrifugal field, because of the growth of primary Si and fusion after colliding between primary Si particles, which compromised the velocity difference of primary Si and primary Mg2Si particles caused by the difference of their densities. Research results have some theory significance and applicative value of project in development of new aluminum matrix composites piston products.     

Detailed Analysis of Oil Transport in the Piston Assembly of a Gasoline Engine

More realistic and useful models of piston ring lubrication can only be achieved if there is a better understanding of the complex mechanisms by which oil flows in this region of the engine. The volume of oil in the piston assembly and its residence time in this high-temperature environment are crucial in determining the quantity and quality of oil available to lubricate the piston rings. Typically models of piston ring pack lubrication focus upon the oil flowing through the piston ring/cylinder interface. However, a number of additional oil flow paths and interactions with gas blow-by have been observed in the piston assembly. This paper presents a model that includes a number of such mechanisms and evaluates their influence on the lubrication of a piston ring pack from a typical automotive gasoline engine. The results indicate that such additional mechanisms are needed to give improved predictions of oil transport they highlight the relative importance of several of these mechanisms and help guide future research.     

C61160大型车床数控化改造

介绍了对Ｃ６１１６０大型车床进行数控化改造的具体实施方案。其中对机床结构的改动以及机床的主轴系统、进给系统和数控系统的改造步骤均作了较详细的介绍。并对调试中遇到的问题提出了解决的办法。改造后的车床在提高生产效率，保证加工质量以及减轻工人劳动强度方面均效果显著。     

润滑油消耗的研究

本文围绕润滑油经气缸、活塞、活塞环流入燃烧室的途径,介绍了气缸内表面的粗糙度和失圆方向。活塞顶岸与气缸套的间隙,油环的追随性 系数、油环的重量、油环与气缸壁的接触面压,第一道环的闭口间隙、滑动面和梯形环角度等因素对润滑油消耗量的影响。