定向装配法在精密主轴装配中的应用

定向装配法是提高精密机床主轴装配精度的有效方法之一.分析了装配过程中主轴前后轴承误差对机床主轴精度的影响,介绍了定向装配方法的原理及实现方法,将这一方法运用在某高精度主轴装配中,取得了较好的效果.     

小型排刀车床动力刀座的精度修正

针对某型动力刀座装配结构,对它在工作过程中出现的发热现象和精度超差原因进行理论分析,得出主轴和轴承配合间隙超差、前后轴承偏心、隔套高度一致性差是导致跳动精度超差及设备发热的主要原因。并提出了具体调整措施,有效提高了动力刀座精度。     

浅谈数控车床主轴轴承的检测与定向装配

主轴系统是数控车床机械部分中的关键部位,其装配精度直接影响到机床的加工精度,而主轴轴承的选型、测量、装配方法至关重要。介绍一种数控车床主轴轴承的检测与定向装配方法,装配后主轴精度高,轴承使用寿命长,性能稳定。     

考虑多影响因素精密机床主轴轴承试验台研制

针对精密机床在不同工况条件下的运转特点,对影响机床主轴轴承精度保持性的原因进行研究,研制了适合作用在不同预紧力、转速、外载荷、安装方式等多种试验条件下的精密机床主轴轴承试验台。介绍了试验台的技术方案和设计参数,绘制了试验台二维、三维模型图,并对试验台轴系、基座等关键零部件进行有限元分析。结果表明,试验台关键零部件均满足设计要求,试验台设计方案合理,能够稳定运行,可以满足多工况下精密机床主轴轴承试验的要求。     

立式双立柱数控工作台的安装工艺设计

数控双立柱车床主轴安装高精度双列短圆柱滚子轴承以保证工作台径向跳动,主轴上部装有大承载推力轴承,用于卸去工作台一部分重力,保证工作台端面跳动。主轴调整的好坏直接关系到机床加工精度。工作台一般采用静压导轨结构,为了保证工作台静压导轨的精度和油膜刚度,要求工作台静压导轨油膜间隙控制在0.03~0.04 mm内,使工作台和工作台底座有良好的接触,才能保证工作台静压导轨的正常使用。主轴精度及工作台和工作台底座配合精度的调整,对机床工作精度起着决定性的作用。立式双立柱车床精度的调整,重点在机床主轴精度调整方面。阐述主轴轴承间隙调整和卸荷垫调整方法。按此方法调整装配能有效保证工作台的工作精度。     

基于故障特征频率的精密机械主轴复合故障定位方法

针对由于撞刀事故引起的精密车床主轴精度下降问题,首先通过主轴振动信号监测,获取故障主轴振动信号频域特征;然后基于主轴结构和轴承特征参数,计算不同故障模式下轴承故障特征频率;最后基于故障特征频率与监测振动信号频率之间的对应关系,定位主轴故障位置。通过主轴拆卸和精度测试,验证了所提故障定位方法的有效性。实验结果表明：角接触球轴承内、外圈损伤是导致主轴精度下降的故障源,理论方法故障定位结果与拆卸实验定位结果一致;采用新轴承重装配后主轴的精度检测结果恢复正常,进一步验证了此故障定位方法的有效性。     

立磨主轴装配和轴承游隙的测量与调整研究

针对某新型立磨关键核心部件主轴装置结构特点和装配精度要求,论述了主轴装置的装配方法及顺序,研究了立磨主轴轴承游隙的测量和调整方法。实践表明:该方案科学合理,有效保证了产品的装配质量和工期要求。     

立式数控车床CK5225高精度主轴装配工艺设计

立式数控车床高精度主轴的装配精度直接影响工作台的精度,从而影响零件的加工质量,所以装配调整主轴的精度至关重要。CK5225系列机床凭借精度高、高速运动平稳、加工零件精度高,得到越来越多用户的青睐。该机床最关键参数是主轴精度高,机床的主轴径向跳动和端面跳动都严格控制在0.005 mm内。通过设计装配工艺、改进装配方法、制造专用工具,保证了精度要求。     

数控车床总装关键工序的装配技术及精度分析

研究装配精度,采用有效的装配方法,对保证产品的质量有着十分重要的意义。文章主要介绍了CKA6150数控车床床头箱在整机总装关键工序中的装配工艺技术及精度检验方法,对床头箱与床身的位置精度、冷态精度和热态精度的相互关系、主轴热位移偏差方向等方面进行了分析研究。在数控车床的现场装配过程中,应用这种装配技术,对于保证机床整机精度的可靠性,提高机床生产效率是一种有效的途径。     

精密球加工机床的静压主轴

一、概述为了加工精密的球形零件,我们设计了专用球加工机床。该机床主轴采用了液体静压轴承。经过调试与试件试切,主轴旋转精度良好,满足了设计的要求。为加工精密球形零件,对静压主轴部件提出了如下要求:(1)主轴回转精度小于0.5微米。(2)主轴能正反转,并需无级调速,范围为100～1500转/分。(3)主轴部件热变形应尽量小。(4)主轴箱轴向移动距离为50毫米,在横向的偏移不大于0.5微米。对于装夹在主轴上的球形零件,主轴的径向与轴向回转精度是影响球的精度的主要     

Investigation of spindle bearing preload on dynamics and stability limit in milling

Many spindle designs offer automatic, speed-dependent preload adjustments to improve the bearing service life. This can result in spindle speed-dependent dynamic properties at the tool tip and errors in process stability predictions. In order to improve stability prediction accuracy for a representative tool and tool holder assembly, the tool tip frequency response functions are measured for different bearing preload values. Using stability models, stability limits are then predicted. Effects of bearing preload on the stability limits are demonstrated via simulations and cutting tests.     

Modeling of spindle-bearing and machine tool systems for virtual simulation of milling operations

This paper presents a general, integrated model of the spindle bearing and machine tool system, consisting of a rotating shaft, tool holder, angular contact ball bearings, housing, and the machine tool mounting. The model allows virtual cutting of a work material with the numerical model of the spindle during the design stage. The proposed model predicts bearing stiffness, mode shapes, frequency response function (FRF), static and dynamic deflections along the cutter and spindle shaft, as well as contact forces on the bearings with simulated cutting forces before physically building and testing the spindles. The proposed models are verified experimentally by conducting comprehensive tests on an instrumented-industrial spindle. The study shows that the accuracy of predicting the performance of the spindles require integrated modeling of all spindle elements and mounting on the machine tool. The operating conditions of the spindle, such as bearing preload, spindle speeds, cutting conditions and work material properties affect the frequency and amplitude of vibrations during machining.     

Characteristics of a spindle bearing system with a gear located on the bearing span

The spindle bearing system is the main source of the total cutting point compliance of machine tool structures. In this work, the static and dynamic characteristics of a spindle bearing system driven by a gear located on the bearing span were investigated using the analytical and finite element methods. Based on the calculated results, a prototype spindle bearing system was manufactured and its static and dynamic characteristics were measured. From the comparison of the experimental results with the calculated results, it was found that the finite element method predicted well the static and dynamic characteristics of the spindle bearing system.     

基于数据驱动和本体建模的数控机床主轴故障诊断与推理

针对目前数控机床主轴系统故障诊断存在方法单一及智能化程度低的问题,提出基于数据驱动和本体建模的机床主轴故障诊断与推理方法。采用EMD对传感器采集的蕴含故障特征的原始信号进行数据处理与分析,提取原始统计特征,在此基础上,构建DBN-RF诊断模型实现深度特征自适应挖掘与故障模式识别。利用Protégé5.1工具结合领域知识构建机床主轴故障本体知识库,将DBN-RF诊断模型的故障辨识结果与本体知识库中的实例进行语义映射,实现故障知识推理,获得故障原因和故障解决策略。基于采集的不同工况下轴承故障数据验证了DBN-RF诊断模型的有效性,最高故障诊断平均准确率可达92.93%;构建实例验证了本体知识库的可重用性和推理功能;最后,设计开发了数控机床主轴健康管理服务系统,实现主轴系统状态实时感知和故障诊断与推理。     

Modelling machine tool dynamics using a distributed parameter tool–holder joint interface

Increasing productivity in machining process demands high material removal rate in stable cutting conditions and depends strongly on dynamic properties of machine tool structure. Combined analytical–experimental procedures based on receptance coupling substructure analysis (RCSA) are employed to determine the stability of machine operating conditions at different tool configurations. The RCSA employs holder–spindle experimental mobility measurements in conjunction with an analytical model for the tool to predict the dynamics of different sets of tool and holder–spindle combinations without the need for repeated mobility measurements. In this paper an alternative approach using the concept of tool on resilient support is adopted to predict the machine tool dynamics in various tool configurations. In the proposed model the tool, represented by an analytical model, is partly resting on a resilient support provided by the holder–spindle assembly. The support dynamic flexibility is measured by performing vibration tests on the holder–spindle assembly. Tool–holder joint interface characteristics are included in the model by considering a distributed elastic interface layer between the holder–spindle and the tool shank part. The distributed interface layer takes into account the change in normal contact pressure along the joint interface and comparing with the lumped joint model used in RCSA it allows more detailed representation of the joint interface flexibility and damping which have crucial roles in machine dynamics. Experiments are conducted to demonstrate the efficiency of proposed model in prediction of milling operation dynamics and it is shown that the model is capable of accurately predicting the dynamic absorber effect of spindle in a tool tuning practice.     

主轴传动部件的热平衡技术研究与应用

分析主轴箱的主要热源以及发热量对整个主轴箱部组精度的影响,采用大流量的恒温油对主轴箱进行冷却与润滑以及优化主轴轴承安装工艺,以保证主轴高速运行的过程中其轴向变形量达到最小。通过试验验证,主轴达到热平衡时其伸长量为0.035 mm。通过对温升与热伸长量的函数进行研究,对轴向热变形进行补偿,以保证机机床在达到热平衡过程中,对工件加工精度的影响最小。     

小模数滚齿机用电主轴的设计与研究

小模数数控滚齿机去掉了传动用的齿轮副、蜗轮蜗杆副等传动元件,刀具轴和工件轴直接与电机轴相联。几何误差和热误差是小模数滚齿机的主要误差来源,为此,设计了一种新型的电主轴。该电主轴采用了主轴电机置于主轴后轴承之后的形式,缩小了主轴轴承位置的径向尺寸,使轴承摩擦产生的热量的散发,减少了电机发热对轴承变形产生的影响;主轴轴承采用了静压轴承的形式,提高了主轴轴承的耐磨性和回转精度。该电主轴的设计能够提高小模数滚齿机的生产效率和加工精度。     

用于主轴热控制的水冷机设计

为了有效抑制机床主轴发热，降低主轴热对机床精度的影响，提出一种用于主轴热控制的水冷机设计方法。根据机床主轴内部热源分布特点，制定机床水冷机的总体设计方案，并开发各功能子模块，在对水冷过程进行功能分析的基础上，提出机床水冷机的控制原理与方法。实验研究表明:机床水冷机可使主轴温度降低30%，热平衡时间缩短45%。     

Thermal characteristics of the spindle bearing system with a gear located on the bearing span

High cutting speeds and feeds are essential requirements of a machine tool structure to accomplish its basic function which is to produce a workpiece of the required geometric form with an acceptable surface finish at as high a rate of production as is economically possible. Since bearings in high speed spindle units are the main heat source of total cutting system, in this work, the thermal characteristics of the spindle bearing system with a tilting axis were investigated using finite element method to improve the performance of the spindle bearing system. Based on the numerical results, a specially designed prototype spindle bearing system was manufactured. Using the manufactured spindle bearing system, the thermal characteristics were measured and compared to the numerical results. From the comparison of the numerical results with the experimental results, it was found that the finite element method predicted well the thermal characteristics of the spindle bearing system.