数控机床进给系统滚珠丝杠刚度分析

滚珠丝杠作为数控机床进给系统的重要元件,其性能直接影响了进给系统的定位精度。对滚珠丝杠的刚度进行分析,通过理论计算和大型ANSYS分析软件两种方法分析了滚珠丝杠扭转刚度和轴向刚度对失动量的影响,为进给系统的机构设计和定位精度提高提供了可靠的理论依据。     

基于ANSYS的滚珠丝杠进给系统静动态特性分析

对一台数控车床滚珠丝杠进给系统的静、动态特性进行有限元分析,讨论了ANSYS中滚珠丝杠副结合面的建模方法。通过进给系统的死区误差和定位误差分析,校核了机床X向的定位精度和重复定位精度。并通过模态分析和谐响应分析,得到了机床进给系统固有频率和振动特性,为进给系统的合理使用和静、动态性能的提高提供了可靠的依据。     

不同指令轨迹条件下滚珠丝杠进给系统运动精度特性研究

滚珠丝杠进给系统是高档数控机床重要部件,其运动精度决定了多轴联动加工机床的加工精度,在高速、高精度滚珠丝杠进给系统中,其指令轨迹参数是影响运动精度的重要因素。基于Simulink和Simscape搭建滚珠丝杠进给系统半物理机电耦合仿真模型,考虑不同指令轨迹参数,开展运动精度仿真及分析。结果显示,指令轨迹的位置、速度和加速度等参数对滚珠丝杠进给系统运动精度有重要影响,因此,在多轴联动加工机床中,合理规划进给系统轨迹参数对于提高其运动精度具有重要意义。     

高速加工中滚珠丝杠进给系统性能分析

本文指出了高速加工中滚珠丝杠进给系统高速化后所面临的一系列问题,并针对几个重要问题进行详细介绍,同时提出了改进措施。最后展望了高速加工中进给系统的发展前景。     

高速数控机床机械性能仿真分析与研究

建立了滚珠丝杠进给系统仿真参数的同时建立了伺服闭环控制模型,并在此基础上对加工中直线切削和圆周运动存在的各种偏差进行了仿真分析,提出了在高速加工中有效减小滚珠丝杠进给系统弹性变形的措施。     

第二讲 数控机床进给系统设计（之一）

叙述数控机床进给系统的传动设计及主要传动件滚珠丝杠及其支承的设计计算。     

加工工件质量及安装位置对滚珠丝杠进给系统动态特性的影响

滚珠丝杠进给系统是数控机床的关键部件,其动态特性与运动精度紧密相关,对数控机床加工精度有重要影响。滚珠丝杠进给系统的动态特性具有明显的时变特征,为探究工件质量及放置位置对滚珠丝杠进给系统动态特性的影响规律,基于集中质量法构建了滚珠丝杠进给系统动力学模型,并利用有限元方法验证了模型精确度。基于所构建的动力学模型开展了工件质量及放置位置对滚珠丝杠进给系统动态特性的影响规律分析,构建了其响应面,结果显示,随着工件质量的增加,滚珠丝杠进给系统固有频率降低;工件位置离工作台重心越近,对系统固有频率影响越小。结果可用于实际加工过程中,指导工件的在工作台面的放置位置选择。     

CKT6150数控车床进给系统的设计

介绍了伺服电机驱动精密滚珠丝杠实现进给运动的设计过程,包括联轴器及轴承的设计;经实践应用表明,进给系统的性能可靠.     

高速滚珠丝杠进给驱动系统机械模型的仿真研究

建立了高速滚珠丝杠进给系统的机械模型。重点分析了机械系统对整个进给驱动系统的影响,并利用MATLAB进行计算机仿真分析与研究。同时指出在高速加工过程中屈服形变引起的轨迹误差,并通过反复修改参数得到优化结果,从而找出进一步改进的措施。     

基于FEM的滚珠丝杠进给系统动态性能分析

用有限元法对一台数控龙门镗铣床滚珠丝杠进给系统的动态特性进行分析,探讨了有限元模型中结合面的建模方法.通过模态分析和谐响应分析,得出了机床进给系统固有频率和振动特性,为进给系统的结构优化和动态性能的提高提供可靠的依据.通过实验证明了有限元分析结果的正确性.     

Mechanical model and contouring analysis of high-speed ball-screw drive systems with compliance effect

The compliance effect of a high-speed ball-screw feed-drive system is modelled in this work. A mechanical model of a ball-screw feed drive system including the motor, ball-screw, coupling, supporting bearing, linear guide and machine structure was developed. It was found that at high acceleration, the mechanical compliance caused a significant contouring error. Smoothing the acceleration and deceleration control input command did improve the transient deviation in the contouring error. However, the steady state error caused by the elastic elongation in the mechanical elements was not improved. It was also shown that the inertia force of the slide and saddle comprised the dominant loading on a high speed machine tool drive mechanism. A topology structure optimisation method is proposed to reduce the moving weight. This method can help the designer efficiently reduce the moving weight of a machine tool axis in a systematic way. More than a 30% weight reduction was demonstrated in a spindle carrier structural design.     

Heat generation modeling of ball bearing based on internal load distribution

In the operation of a machine tool (MT), the frictions in ball bearings entail sudden and violent heating of the balls which dominants its thermal deformation, and subsequently results in degradation of its accuracy and performance. Modeling of the heat generation in a bearing is a quite difficult job because of the constantly changing characteristics. In this paper, an analytical approach was proposed to calculate the heat generation rate of supporting bearing in a ball-screw system of the MT, with consideration of the operating conditions, such as rotation speed and external loads of the machine tool. The influences of operating conditions to internal load distribution, contact angles and heat generation rate of ball bearings were analyzed. The friction torque due to the applied load and the sliding torque within the contact area were discussed in detail. Experiments were carried out in a high-speed ball-screw system to verify the validity of the presented analytical method. The work described in this paper can be seen as a foundation for the accuracy thermal modeling and thermal dynamic analysis of the ball-screw system in the machine tools.     

Experimental evaluation of mechanical and electrical power consumption of feed drive systems driven by a ball-screw

An experimental analysis of the mechanical and electrical power consumption of feed drive systems is presented in this paper. The main components affecting the power consumption are the motor, bearings, ball-screw, and table. The power consumption of the motor has been investigated experimentally through the study of the electrical efficiency. The efficiency has been calculated from the acquired angular velocity and supplied torque for several velocities and loads. The study shows how the working conditions of the motor heavily influence the efficiency of the motor and therefore the power consumption of the whole feed drive system. Moreover, the mechanical power consumption of each component of the feed drive has been investigated, showing that the main component responsible for the consumption is the ball-screw. Thus, in order to clarify the influence of the constructive parameters of the ball-screw on the power consumption, four kinds of ball-screws differing in the lead dimension and the preload condition have been considered. Furthermore, it clarifies the relation between the power consumption of the feed drive system and the working velocity of the table. Finally, the advantages and disadvantages of each feed drive mechanical configuration are discussed, emphasizing that the driven factor that affects the power consumption the most is the angular velocity, due to the trade-off between the motor efficiency and the mechanical power loss from the friction of the components in relative motion. This research can help the selection of the lead of the ball-screw, from an energetic point of view, in order to get higher efficiency of the feed drive.     

高速滚珠丝杠进给驱动系统屈服形变分析

文中建立了高速滚珠丝杠进给系统屈服形变模型。以驱动装置的屈服形变作为主要研究对象,指出了高速加工中的机械屈服形变会引起明显的轨迹误差,通过平滑加、减输入控制命令可以改善轨迹误差中的瞬态偏差,机床基础弹性伸缩量引起的稳定性误差还有待进一步改善。     

Suppression of harmonic positioning errors in ball-screw drives using Adaptive Feedforward Cancellation

Harmonic positioning errors can negatively affect the positioning accuracy of the ball screw drive system. This paper addresses the problem of harmonic positioning error suppression in ball-screw drives using Adaptive Feedforward Cancellation (AFC). AFC method is integrated with the dual (i.e., rotational and translational) feedback structure used in ball-screw drives. The ability of AFC to quench harmonic positioning errors originating from multiple input sources is analyzed, considering the effects of the commanded trajectory, motor torque ripples, rotary encoder measurement errors, and lead errors coming from the ball-screw mechanism. A new approach for parameter tuning of the AFC resonators is proposed which considers both the performance deterioration issue at frequencies outside the target harmonics, and also the robust stability requirement in the sense of limiting the peak loop sensitivity value. Effectiveness of the proposed AFC scheme for ball-screw drives is validated in experiments, demonstrating successful rejection of time-periodic machining force disturbances, as well as mitigation of displacement-periodic lead error and misalignment type errors. In the case of machining force rejection, 50–78% improvement is achieved in the standard deviation of the translational positioning error. In the case of position dependent disturbances, the improvement is typically in the 10–20% range and is most effective during constant velocity motion.     

加工中心双驱滚珠丝杠副动态性能试验平台设计

为了研究加工中心双驱滚珠丝杠副在高速运行状态下的性能状态,根据双驱滚珠丝杠进给系统的主要检测指标要求,计算确定了机械系统的方案,建立了Pro/E三维机械模型,进而设计了一种用于检测双驱滚珠丝杠副的动态性能试验平台。该试验平台上安装传感器,可以对双驱滚珠丝杠副的同步性、加速度、速度、热位移等动态性能参数进行测试,为进一步研究双驱滚珠丝杠性能提供可靠的实验数据。     

滚珠丝杠式惯容器非线性建模与参数辨识

针对滚珠丝杠式惯容器存在的非线性力学特征,首先,分析了滚珠丝杠式惯容器的工作原理,对惯容器的主要部件进行了非线性力学分析,建立了考虑摩擦、间隙以及丝杠弹性力的惯容器非线性力学模型;然后,在数控液压伺服激振试验台上进行了惯容器的力学性能试验,得到了惯容器在不同惯容系数以及不同激振输入下的力学响应特性;最后,根据试验结果分析了摩擦和间隙对惯容器力学性能的影响,得到了便于参数辨识的惯容器力学模型结构,实现了惯容器输出力仿真与试验结果的分析和对比。结果显示,二者在一个周期内的均方根值误差不超过7%,非线性模型呈现出良好的拟合精度,证明了所述方法的可行性和有效性。     

Numerical solution, simulation and testing of the thermal dynamic characteristics of ball-screws

This research focuses on the characteristics of how a ball-screw changes its temperature corresponding to the periodic change of the end-most heat source. Based on the theory of heat transfer, this paper supplies a numerical solution to the non-homogeneous equation of heat transfer through the group explicit (GE) finite difference approach. The temperature distribution for the ball-screw at different times and directions is shown. By simulating and modeling the temperature field and thermal deformation of the ball-screw under periodically varying heat sources, this paper describes the thermal dynamic characteristics of the ball-screw under such conditions. By testing the thermal dynamic characteristics of the ball-screw, the numerical solution is validated.     

应用差动滚珠丝杠机构提高位移精度的研究

在现有滚珠丝杠系统的基础上,提出了一种应用差动工作原理来提高位移精度的差动滚珠丝杠机构,从而有效地解决了机械系统对位移精度的高要求。     

Numerical solution,simulation and testing of the thermal dynamic characteristics of ball-screws

This research focuses on the characteristics of how a ball-screw changes its temperature corresponding to the periodic change of the end-most heat source. Based on the theory of heat transfer, this paper supplies a numerical solution to the non-homogeneous equation of heat transfer through the group explicit (GE) finite difference approach. The temperature distribution for the ball-screw at different times and directions is shown. By simulating and modeling the temperature field and thermal deformation of the ball-screw under periodically varying heat sources, this paper describes the thermal dynamic characteristics of the ball-screw under such conditions. By testing the thermal dynamic characteristics of the ball-screw, the numerical solution is validated.