凹面轮廓凸轮轴成形磨削工艺研究

分析带有凹面轮廓的凸轮轴(简称凹面凸轮轴)数控磨削加工难点,提出采用大砂轮与小砂轮复合数控成形磨削凹面凸轮轴新工艺。给出了小砂轮半径的计算公式,通过计算凹面轮廓的最小曲率半径,对比判断是否需要切换砂轮。详细分析了大砂轮与小砂轮复合数控成形磨削凹面凸轮轴新工艺过程,并在CNC8325B全数控凸轮轴超高速复合磨床上进行了高速磨削加工实验,实验结果表明,该工艺方法可以实现凹面凸轮轴轮廓的磨削成形加工,满足了加工精度要求。     

中国机床市场近期需求一瞥

汽车行业:加工箱体类零件的加工中心、加工回转体零件的数控车床和车削中心、数控高速滚齿机、数控蜗杆砂轮磨齿机、曲轴磨床、曲轴车拉机床、凸轮轴磨床、活塞车床等。机械基础件及机床工具行业:各类加工中心、数控车床数控大平面砂轮磨齿机、数控坐标磨床、数控导轨磨床、数控内圆磨床、精密小孔珩磨机、数控万能工具铣床、数控蜗杆砂轮磨齿     

数控立式磨B轴伺服回转进给机构设计

数控立式磨床的B轴功能即驱动磨削主轴进行伺服摆动的进给轴,无此功能的数控立式磨床磨削平面时磨削主轴垂直于加工平面（见图1）,只能用碗形砂轮端面磨削,有螺旋线的加工纹路;而具备B轴功能后（见图2）,磨削主轴可与磨削平面成小角度,用平砂轮外圆磨削,其磨削平面效果优于前者,且无明显加工纹路,加工平面更光洁。加工锥面时,无B轴功能数控立式磨床需将平砂轮外圆修斜,砂轮截面为梯形;而有B轴功能数控立式磨床只需将磨头转角度即可,砂轮截面为矩形;矩形截面砂轮的优势在于,其加工时各个切削点的线速度相同,更有利于高精度磨削加工。     

直线成形面数控展成磨削技术研究

研究在数控平面磨床上利用碟形砂轮对直线成形面进行精密磨削加工。综合直线成形面的常见磨削技术,采取数控展成加工的原理,利用数控平面磨床的两轴联动,用碟形砂轮或斜边砂轮对直线成形面进行展成磨削。分析数控展成磨削的磨削原理、表面成形机理、砂轮的修整技术以及砂轮的安装误差和形状误差、磨削的进给行距及数控系统等因素对成形面精度的影响,得到了直线成形面的数控展成磨削新技术。     

立式数控磨床砂轮修整装置

介绍了主要用于立式数控磨床大型回转支承双圆弧滚道加工的数控砂轮修整装置。为保证砂轮的修整精度和表面质量，结合数控磨床的结构特点，开发了一种机、电、液、气相集成的数控砂轮修整装置。     

基于VERICUT的双圆弧齿廓弧齿锥齿轮成形磨削仿真

通过VERICUT加工仿真验证了数控成形磨削法加工双圆弧齿廓弧齿锥齿轮的可行性。研究了数控成形法加工锥齿轮的刀具轨迹和圆弧齿廓弧齿锥齿轮的齿面方程,通过砂轮磨削面和齿面的接触条件式求出成形砂轮轴向截形;然后,提出数控成形磨齿机联动轴数的选取准则,并在VERICUT中建立机床、成形砂轮和毛坯的模型;最后,对双圆弧齿廓弧齿锥齿轮进行加工仿真,证明了数控成形磨削法可用于加工该类齿轮,为数控成形磨削法在锥齿轮上的应用提供了技术支持。     

数控凸轮磨床的研制

传统凸轮加工采用靠模成型法,它不仅加工精度较低,且加工范围受靠模限制。数控凸轮磨削摆脱了这种束缚。本文提出一种砂轮中心轨迹不受砂轮半径变化的新加工方法,从而使凸轮在加工过程中,不必考虑因砂轮变化而对砂轮中心轨迹的修正。文中介绍了该机床的计算机控制系统和系统的软件。     

数控端面外圆磨床成形砂轮的修整方法

介绍一种不带斜轴功能数控系统的数控端面外圆磨床,运用宏程序对X轴(砂轮架)倾斜角度的三角函数计算与插补控制,实现对其成形砂轮进行修整的方法。为了更好地加工轴类零件的端面,且保证能安全地磨削加工砂轮,数控端面外圆磨床的砂轮架与工作台的角度应为60°,使砂轮斜切入磨削加工。在成形砂轮修整时,由于X轴与Z轴并非垂直,而是成60°,因此,需再对修整程序进行三角函数的计算和程序插补控制,使Z轴跟随X轴自动插补,将砂轮修整出理想的轮廓状态。     

基于VERICUT的四圆弧齿轮成形磨削加工仿真

根据成形法磨削加工原理,应用VERICUT软件对四圆弧齿廓齿轮进行数控仿真加工。首先根据数控成形磨齿机建立机床模型、毛坯模型,并依据四圆弧齿廓齿轮成形磨削砂轮截形建立砂轮模型,再参照机床结构和成形磨削运动编写仿真数控程序,最后在VERICUT软件平台进行四圆弧齿轮的数控仿真加工并对仿真结果进行分析。分析结论表明,仿真加工能够满足设计精度要求,且数控程序是正确的。     

高精度铲齿成形铣刀铲磨用砂轮精确修形的研究

论述了用计算机辅助设计的方法计算铲磨砂轮截形 ,用数控砂轮修形系统修整砂轮形状 ,这种方法满足了加工高精度铲齿成形铣刀的需要     

高速钢材料的粗金刚石砂轮轴向进给数控磨削机理研究

根据正交试验确定了影响高速钢材料的粗金刚石砂轮轴向进给数控磨削表面粗糙度值Rα的最主要因素是进给速度Vfo。在此基础上，进行进给速度巧单因素数控磨削实验，对数控磨削后表面粗糙度值进行了分析。分析结果表明，要用粗金刚石砂轮进行轴向精密加工，采用具有较多的磨粒数且磨粒均匀分布在轴向和周向的砂轮和采用较低的进给速度对精密加工更有利。     

基于UG的车链轮设计与制造

针对原链轮存在的缺陷,重新设计了齿形,利用AutoCAD、CAXA与UG软件设计链轮,并进行仿真模拟,将得到的NC代码程序导入数控机床加工。加工后得到的链轮经适当热处理即可使用,在尺寸精度、硬度、强度等方面达到了要求。     

基于PLC对YB3180滚齿机传动链的数控改造

本文介绍采用数控法改造YB3180滚齿机,减少并缩短了传动链的数量和长度,提高了滚齿机的加工精度,扩宽了加工范围,并且还可以用于特种圆锥齿轮加工。     

基于PLC的数控齿条磨齿机控制系统

为了提高齿条磨齿机加工精度和效率,提出了齿条磨齿机数控化方法。数控齿条磨齿机控制系统以可编程控制器为基础,完成砂轮的旋转运动、工作台的直线运动和液压缸的纵向进给运动;应用光栅尺显示砂轮的垂直进给量和反馈机床分齿运动,采用人机互动界面输入控制命令和加工数据,并实时反映机床运动情况。给出了控制系统结构框图,详细介绍了系统的硬件设计和软件设计。数控齿条磨齿机试用结果表明该控制系统运行平稳,加工精度符合要求。     

Effect of steering wheel heating system on hand thermal sensation

A numerical study is conducted to verify the effect of the steering wheel heating system for enhancing the thermal sensation of the hand. First, a numerical study was conducted to quantify the sensory index called thermal sensation. A five-layer skin model was developed, and the reliability of the model was confirmed by comparing it to previous research results. The temperature and its rate of changes for skin layers were predicted by the numerical study, while the relationship between the numerical results and the hand thermal sensation data from ISO/TS 13732-2:2001 were quantitatively analyzed. A one-dimensional unsteady heat transfer model dealing with a steering wheel was designed and developed and it was determined whether the wheel heating system is effective as an auxiliary personal heating system for electric vehicles in the cold winter. Consequentially, even a small amount of electrical energy could provide a meaningful effect to hand thermal sensation.

     

A manufacturing model of an end mill using a five-axis CNC grinding machine

This paper presents a manufacturing model of a flat-end mill using a five-axis computer numerical control (CNC) grinding machine. The profile of the helical groove can be precisely calculated using a given wheel profile and the relative movements between the workpiece and the grinding wheel. The results of the calculation of the numerical control (NC) data for all the grinding processes of the end mill are fully presented in the paper. The NC data for the machining end mill were generated from the developed program by using the given design parameters of tool geometry, wheel geometry, wheel setting, and machine setting. The effects of the design and manufacturing of the end mill were analyzed based on the computer simulation and experiment results. This study provides a practical and efficient model for the manufacturing of an end mill using a CNC grinding machine with simple programming techniques. The prediction of the end mill geometry for the designing of the proper configuration of the end mill before manufacturing and generating the NC code for machining in a CNC machine is necessary to save time and to reduce the manufacturing cost.     

基于RENESAS嵌入式MCU的数控小车系统

通过对两轮驱动小车运动模型的分析,运用数控机床上的程序加工原理和在线编程方法,实现了小车的轨迹可在线编程,并提出一种两轮机器人小车轨迹控制的设计方法。     

Numerical simulation and experimental research on the wheel brush sampling process of an asteroid sampler

To examine the environmental characteristics of the microgravity force and the weathered layer on an asteroid surface, a symmetric wheel brush asteroid sampler is proposed for the collection of particles on the asteroid surface. To study the influence of the wheel brush rotation speed on the sampling efficiency and the driving torque required for the wheel brush, the contact dynamics model between particles and sampling wheel brushes is established and a simulation and experimental verification of the sampling process are conducted. The parameter calibration of the sampled particles is studied first, and the calibrated particle parameters are used in the numerical simulation of the sampling process. The sampling results and the particle stream curves are obtained for the working conditions of different rotation speeds, and the effects of different parameter settings on the sampling efficiency are analyzed. In addition, a set of rotating symmetrical sampling wheel brush devices is built for the ground test, and the dynamic torque sensor is used to test the torque change of the wheel brush during the sampling process. The relationship between the speed of the wheel brush and the driving torque of the wheel brush motor is determined by comparing the simulation results with the test results. Results indicate that when the rotating speed of the wheel brush is faster, the sampling efficiency is higher, and the driving torque required for the sampling wheel brush is greater. Moreover, a numerical simulation analysis of the sampling process of the wheel brush sampler in a microgravity environment is conducted to determine the optimal speed condition, and the brushing test of the wheel brush sampler in the microgravity environment is verified with the drop tower method. This research proposes the structural optimization design and motor selection of a wheel brush asteroid sampler, which provides important reference value and engineering significance.     

磨床砂轮破裂后防护罩变形过程的有限元分析

建立了一种用于磨床砂轮破裂后防护罩变形过程分析的有限元模型。采用显式时间积分格式,磨床安全防护罩采用一点积分的４节点双线性壳单元。材料服从等向强化塑性准则。砂轮、法兰、主轴及支座采用一点积分的８节点实体单元。接触搜寻采用主从面法,接触力由罚参数计算,摩擦力由经典摩擦定律决定,砂漏控制采用前置参数方法。采用间接方法验证了本文力学模型的正确性。实例表明,本文的模型切实可行。