Thermal Model of High-Speed Spindle Units

For the purpose to facilitate development of high-speed Spindle Units (SUs) running on rolling bearings, we have developed a beam element model, algorithms, and software for computer analysis of thermal characteristics of SUs. The thermal model incorporates a model of heat generation in rolling bearings, a model of heat transfer from bearings, and models for estimation of temperature and temperature deformations of SU elements. We have carried out experimental test and made quantitative evaluation of the effect of operation conditions on friction and thermal characteristics of the SUs of grinding and turning machines of typical structures. It is found that the operation conditions make stronger effect on SU temperatures when rpm increases. A comparison between the results of analysis and experiment proves their good mutual correspondence and allows us to recommend application of the models and software developed for design and research of high-speed SUs running on rolling bearings.

Temperature prediction model for a high-speed motorized spindle based on back-propagation neural network optimized by adaptive particle swarm optimization

To predict the temperature of a motorized spindle more accurately,a novel temperature prediction model based on the back-propagation neural network optimized by adaptive particle swarm optimization(APSO-BPNN)is proposed.First,on the basis of the PSO-BPNN algorithm,the adaptive inertia weight is introduced to make the weight change with the fitness of the particle,the adaptive learning factor is used to obtain different search abilities in the early and later stages of the algorithm,the mutation operator is incorporated to increase the diversity of the population and avoid premature convergence,and the APSO-BPNN model is constructed.Then,the temperature of different measurement points of the motorized spindle is forecasted by the BPNN,PSO-BPNN,and APSO-BPNN models.The experimental results demonstrate that the APSO-BPNN model has a significant advantage over the other two methods regarding prediction precision and robustness.The presented algorithm can provide a theoretical basis for intelligently controlling temperature and developing an early warning system for high-speed motorized spindles and machine tools.

Model of Rotation Accuracy of High-Speed Spindles on Ball Bearings

For the purpose to improve a design quality of high-speed spindle units, we have developed mathematical models and software to simulate a rotation accuracy of spindles running on ball bearings. In order to better understand the mechanics of ball bearings, the dynamic interaction of ball bearings and spindle unit, and the influence of the bearing imperfections on the spindle rotation accuracy, we have carried out computer aided analysis and experimental studies. When doing this, we have found that the spindle rotation accuracy can vary drastically with rotational speed. The influence of bearing preload has a secondary importance. Comparison of the results of these studies has demonstrated adequacy of the models developed to the real spindle units.

Research Progress of Key Technology of High-Speed and High Precision Motorized Spindles

High speed machining and high precision machining are two tendencies of themanufacturing technology worldwide. The motorized spindle is the core component of the machine toolsfor achieving the high speed and high precise machining, which affects the general developmentlevel of the machine tools to a great extent. Progress of the key techniques is reviewed in thispaper, in which the high speed and high precision spindle bearings, the dynamical and thermalcharacteristics of spindles, the design technique of the high frequency motors and the drivers, theanti-electromagnetic damage technique of the motors, and the machining and assembling technique areinvolved. Finally, tha development tendencies of the motorized spindles are presented.

Lightweight design of 45000r/min spindle using full factorial design and extreme vertices design methods

Factors for determining the spindle size are the shaft diameter, positions of bearing and motor, and entire length of the spindle. Then, it is important to find the assembling of the optimal design variables, which satisfy the stiffimss and rotational speed required to the spindle. A general full factorial design method was used to verify some factors that affect the natural frequency of a spindle. It is verified that the shorter shaft length and bearing span length represent the higher natural frequency, and there are some effects according to the change in the levels of factors. The detailed spindle dimension is determined by applying an EVD method, which can define the optimal bearing position through considering the limiting condition. Based on the estimated regression model, the optimal spindle size and bearing distance that can improve the primary natural frequency are obtained, and the influence of design factors on the natural frequency is also analyzed.

主轴结构参数对静刚度贡献度的分析

为了研究主轴芯轴的结构参数对主轴径向静刚度的影响规律,以某型号主轴为研究对象,通过有限元模型静力学分析主轴径向静刚度。将主轴芯轴的结构参数简化为12个主要结构参数,采用单一变量法和相关性分析法分析结构参数和主轴径向静刚度的相关性,确定与主轴径向静刚度显著相关的结构参数。运用正交试验-方差分析法分析关键结构参数对主轴径向静刚度的贡献度。结果表明:主轴悬伸部分和轴承跨距之间的结构参数对主轴径向静刚度的贡献度分别为20.3%、69.8%,可以通过定向改变主轴芯轴结构参数控制主轴径向静刚度,提高主轴的刚度特性。

一种轴承预紧用施力检测装置的设计与应用

当机床主轴单元配置NN系列圆柱滚子轴承时,为增强轴承刚性、提高主轴回转精度等性能指标,需对所配置的主轴轴承施加适当的预紧力以调整其径向游隙。目前,常用的冲击轴承锁紧螺母的方式是向轴承直接或间接地施加轴向预紧力,此施力方式不仅会使轴承内环端面相对主轴轴肩产生一定的倾斜,从而影响后序相关尺寸的测量精度,还难以快速得到需要的轴承游隙量,以至于影响装配效率。基于上述原因,设计了一种能够向NN系列主轴轴承提供平稳轴向力的施力检测装置,并在某知名品牌的TS-A0620和TS-A0823两种型号主轴单元的装配过程中试用。统计数据显示,该装置对提高主轴轴承的装配精度和提升主轴单元装配效率起到了积极作用。因此,对该施力检测装置的结构进行推广和使用具有一定的实际意义。

高精主轴装配工艺设计与测试

主轴单元是数控机床的重要功能部件之一,其装配质量将影响机床的加工精度及稳定性等性能指标。为满足数控机床高精高速的实际需求,降低机床主轴单元的故障率,对主轴运转噪声大、轴承温升过高、切削工件表面有振纹等常见故障现象进行研究。结合上述故障产生的原因,分别对相关装配过程作了梳理和总结,如:影响主轴运转噪声的主轴组件动平衡校核工序;影响轴承温升及切削性能的选择配置主轴轴承等工序。通过对主轴单元的温升测试及抗振性切削测试,从而验证了所述装配工艺的正确性和合理性,具有一定的借鉴价值。

Investigations on lubrication characteristics of high-speed electric multiple unit gearbox by oil volume adjusting device

In this paper,a numerical simulation model of the flow field in a gearbox with an oil volume adjusting device is established for the first time to study its influence on the lubrication characteristics of a high-speed electric multiple unit(EMU)gearbox.The moving particle semi-implicit(MPS)method is used to numerically simulate the internal flow field of the gearbox of the high-speed EMU under working conditions.The effects of the velocity of the high-speed EMU,the immersion depth,and the oil sump temperature on the power loss of the gears and the lubricant quantity of each bearing are studied and provide an effective tool for the quantitative evaluation of the lubrication characteristics of the gearbox.The lubrication characteristics of the gearbox under different working conditions are studied when the oil volume adjusting device is closed and opened.The results show that the oil volume adjusting device mainly changes the amount of lubricant stirred by the output gear by changing the flow rate of lubricant from the cavity pinion(Cavity P)to the cavity gear(Cavity G),and thus affects the power loss of gears and the lubricant quantity of each bearing.

基于ANSYS二次开发的机床主轴单元分析系统

基于VB和ANSYS提供的二次开发工具APDL,建立了数控机床主轴单元参数化分析系统。此系统具有友好、方便、易用的人机交互界面,对复杂、难于理解和掌握的ANSYS命令流进行了后台封装,避免了大量的重复性分析工作,提高了分析效率,为机床主轴单元的合理设计提供了依据。

高速电主轴过盈联结装置的设计

介绍了一种适用于高速高精度数控机床电主轴部件的轴向定位与扭矩传递装置———阶梯过盈套，它是一种可拆式过盈联结装置。文中阐述了该装置的结构特点和设计计算方法，分析了各因素对其承载能力的影响。通过设计实例。

重复控制及其在变速非圆车削中的应用

为了提高变速非圆车削中直线伺服单元的跟踪精度和鲁棒性 ,建立了变速非圆车削的进给驱动直线电机、运动控制目标函数、主轴变速、切削力等的数学模型 ,分析了主轴变速精度对直线伺服单元控制的影响。应用重复控制理论设计了适于直线伺服单元的重复控制器 ,给出了详细的设计过程和稳定性分析 ,对控制器的性能进行了仿真分析。结果表明 ,基于重复控制的直线伺服单元能很好地跟踪变速非圆车削中刀具运动的目标值 ,能抑制波动的切削力对跟踪精度的影响。

无心车床空心主轴系统振动特性分析及结构优化

利用Pro/E建立了空心主轴单元的三维模型,采用ANSYS对空心主轴单元进行了振动特性分析。通过在空心主轴上选取的6个关键节点,并取前轴承不同位置,对比分析不同前轴承位置时的固有频率及相应6节点处的振动特性,得到如下结论:刀具和调刀套节点处的振动对棒材加工精度影响最大,并在此基础上对空心主轴结构进行优化,提高了加工精度。

主轴单元参数化建模、分析与优化设计

为实现主轴单元静动态特性的快捷分析,本文提出了主轴单元有限元建模基本参数的概念,建立了主轴单元通用有限元简化模型。以某厂新型五面体加工中心主轴单元为研究对象,利用简化模型得到了主轴单元的静刚度和前十阶模态。与简化前的分析结果比较,证明了简化模型的正确性。分析了不同轴承预紧工况下前两阶固有频率的变化,通过对主轴单元进行动态优化设计,使一阶固有频率提高了32.2%,主轴重量减少了42.9%。

数控机床主轴部件变形的有限元分析

利用有限元分析方法进行优化设计,在产品设计阶段就能对主轴部件静、动态特性作出符合实际的预测,使数控机床主轴部件实现优化设计,进而提高产品一次设计成功率、缩短产品开发周期,提高数控机床产品的设计水平。

超高速数控机床主轴单元的设计研究

分析讨论了超高速数控机床对主轴单元性能的要求．结合实际课题，对超高速数控机床的主轴单元典型结构———电主轴的设计进行了详细论述，为开发超高速数控机床主轴单元提供了必要理论依据和设计方法．

基于圆形统计分析的麻醉恢复室护士梭形排班法的创建及应用

使用圆形统计分析法,分析3 462例麻醉恢复室患者出入室时间分布特点呈梭形分布,根据此规律,麻醉恢复室护士实施梭形排班法,此方法能均衡护士的工作量,提高人力资源利用率及实际床护比,保障患者安全。

全陶瓷主轴-轴承单元的动力学研究

目的研究全陶瓷电主轴预紧力与固有频率的关系,为优化预紧力提供软件分析模型.方法应用赫兹理论计算出在全陶瓷角接触球轴承预紧后的接触应力,接触变形和静接触刚度的数值解,同时在改进传统的弹簧阻尼式主轴动力学软件仿真分析模型的基础上,计及轴承预紧后轴承的静接触刚度,以全陶瓷主轴-轴承单元为研究对象进行有限元结构分析,所得结果通过赫兹计算分析的数值解矫正,分析其动力学特性.结果全陶瓷主轴-轴承单元模型通过模态分析所得三阶固有频率和振型与模态实验分别相差19.59%、1.27%、16.06%;而电主轴传统分析模型所得三阶固有频率和振型与锤击实验分别相差24.39%、14.47%、33.78%.结论通过实验数据验证,全陶瓷主轴-轴承单元模型在分析全陶瓷电主轴动力学特性上更接近模态实验的结果,能够得到更为准确的固有频率和振型.

车铣复合加工中心电主轴的稳定性分析和实验研究

电主轴单元是车铣复合加工中心的核心功能部件。利用ANSYS对电主轴系统完成了自由模态以及两种考虑轴承支承的约束模态分析。并针对电主轴单元进行了现场实验,测得主轴实际模态。综合分析理论计算与实验结果表明计算的自由模态与主轴实际模态区别较大,模态分析时必需考虑轴承的支承作用,并且用两组弹簧才能很好地模拟QBC型角接触球轴承组的支承约束。设计的电主轴满足工作要求。

陶瓷轴承主轴单元动特性的实验研究

对陶瓷轴承主轴单元的动态性能特点进行了实验研究。研究发现，在相同预紧和脂润滑条件下，陶瓷轴承主轴单元的阻尼系数比钢轴承主轴单元小，主轴端部的直接动柔度比钢轴承主轴单元大。研究结果为采用陶瓷轴承主轴单元的高速和超高速数控机床的动态设计提供了实验依据。