基于三维移动载荷理论的细长轴工件加工过程振动研究

发布时间：2018-03-17 09:39

本文选题：切削加工　切入点：振动响应　出处：《大连理工大学》2013年博士论文　论文类型：学位论文

【摘要】：在切削加工中,细长轴工件是难加工零件之一,工件振动、加工稳定性、加工质量都是必须解决的关键问题。尤其是旋转工件表面上移动载荷的作用,工件振动与切削力的相互影响,都加剧了切削工件的振动甚至引起颤振,制约了加工质量和生产效率的提高,影响加工过程顺利进行。因此,研究切削加工过程中细长轴工件的振动规律,己成为实施和解决细长轴工件切削加工技术的瓶颈环节,是亟需解决的关键技术。本文从移动载荷作用下旋转细长轴工件振动分析的角度,针对切削加工过程中三维移动切削力作用下旋转工件的振动问题,采用理论建模与实验研究相结合的方法,开展了车削、外圆磨削加工过程中三维移动载荷作用下旋转细长轴工件的振动研究。 (1)考虑了切削加工过程中移动载荷的作用,以及工件的变质量、变直径、变刚度等时变特性因素的影响,用Rayleigh连续梁振动理论,建立了切削加工过程中三维移动载荷作用下旋转细长轴工件振动的动力学模型和二阶耦合微分方程。此外,还考虑了工件表面的再生效应的影响,建立了切削加工过程中三维移动载荷作用下旋转工件振动的延时动力学模型和二阶延时微分方程。用上述模型研究了车削、外圆磨削加工过程中旋转细长轴工件的振动和颤振问题,并对工件振动方程进行求解和理论分析。 (2)建立了切削加工过程中三维移动载荷作用下旋转工件振动的转子动力学模型,将切削加工过程中细长轴工件的振动简化为质量集中系统的已加工、在加工和待加工的三转子动力学系统,考虑了加工过程中工件质量和直径随时间变化,以及加工表面的再生效应对工件振动的影响。 (3)开展了切削加工过程中工件振动的稳定性研究,考虑了工件和刀具两者振动相互作用的影响,用工件振动方程和质量集中系统的刀具振动方程,建立了车削工件颤振稳定性分析模型,求解车削用量临界极限值,从而避免工件颤振发生。 (4)分析了切削加工过程中工件的不同夹紧方式及其边界条件的建立,并求解工件的振动方程；用理论计算方法,分析了车削、外圆磨削加工过程中切削用量、工件直径等参数对工件振动及其稳定性的影响。 (5)进行了切削加工振动实验,对移动载荷作用下工件振动的理论模型进行验证；对加工中不同夹紧边界下(如车削、磨削)的工件、刀具和刀架进行模态分析及其参数识别；分别开展了车削和磨削加工过程中的工件振动、加工精度和表面粗糙度的测量实验。为了测量外圆磨削力,自主研制了外圆磨削用压电式测力装置,并对该装置进行了标定、精度分析和测力实验。本文对细长轴工件振动的研究表明,切削加工过程中移动载荷作用、旋转工件的质量和直径的时变特性对工件振动都有影响,移动载荷作用下旋转细长轴工件振动模型能够准确地反映加工过程中工件的振动规律,为今后进一步开展切削加工过程中移动载荷作用下不同截面的细长轴工件的振动研究奠定了良好的基础。
[Abstract]:In machining, the workpiece is difficult to machining the slender shaft of the workpiece vibration, machining stability, machining quality are the key problems to be solved. Especially the rotation of the workpiece surface moving loads, mutual influence of workpiece vibration and cutting force, have exacerbated the vibration cutting workpiece and even cause flutter constraints the processing quality and production efficiency, effect of processing smoothly. Therefore, vibration of slender shaft of the workpiece during machining process, has become the bottleneck of implementation and solve the slender parts machining technology, is the key technology to be solved. In this paper, from the analysis of moving loads of rotating shaft vibration of workpiece aiming at the vibration problems of rotating the workpiece, 3D movement of cutting force under the method of theoretical modeling and experimental study of the combination, carry out turning Study on 3D vibration, moving load of rotating shaft workpiece grinding process.
(1) effect of moving load in cutting process is considered, and parts of the variable quality, variable diameter and variable characteristics of variable stiffness etc., with Rayleigh continuous beam vibration theory, establishes the dynamic model of 3D moving loads of rotating shaft workpiece vibration and two order coupled differential equations of cutting in the process. In addition, we also consider the effect of regeneration effect on the surface of the workpiece, a delay dynamics model of rotating workpiece vibration of three-dimensional moving loads and two order delay differential equations in a machining process. Turning was studied by using the model, vibration and flutter of workpiece rotating shaft grinding process. And the solution and theoretical analysis on the workpiece vibration equation.
(2) establish a dynamic model of the rotor rotating workpiece vibration of three-dimensional moving loads during the machining process, the vibration of slender shaft workpiece during machining process has been simplified to processing quality of centralized system, the three rotor dynamic system processing and machining, the workpiece quality and diameter changes with time in the process of consideration the effect and surface regeneration effect of workpiece.
(3) carried out a study on the stability of workpiece vibration during machining process, considering the influence of the tool vibration both the workpiece and the interaction of the centralized tool vibration equation of the system with the workpiece vibration equation and the quality analysis model is established to solve the cutting chatter stability, turning a critical limit, so as to avoid the flutter.
(4) of different clamping workpiece during the machining process and its boundary conditions, and the vibration equation of the workpiece; with the help of theoretical calculation, analysis of turning, grinding cutting amount of process, the influence of diameter parameters on the vibration and stability.
(5) the machining vibration experiment, the theoretical model of the workpiece vibration under the action of moving loads is verified; on different clamping processing boundary conditions (such as turning, grinding) of the workpiece, the tool and holder of modal analysis and parameter identification respectively; the workpiece vibration turning and grinding process, machining precision and the surface roughness measurement. In order to measure the degree of grinding force is developed with piezoelectric cylindrical grinding force measuring device, and the device was calibrated, precision analysis and testing.
This paper studies on the slender shaft workpiece vibration show that the moving load cutting process, rotating the workpiece quality and the diameter of the time-varying characteristics have influence on the workpiece vibration, axial vibration model of rotary slender workpiece under moving loads can accurately reflect the vibration of workpiece in machining process, for further cutting process in the study of vibration loads of different cross-section slender shaft movement of the workpiece has laid a good foundation.

【学位授予单位】：大连理工大学
【学位级别】：博士
【学位授予年份】：2013
【分类号】：TG506;TH133.2

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