【作者】 黄强；

【导师】 张根保；

【作者基本信息】 重庆大学 ， 机械制造及其自动化， 2008， 博士

【摘要】 “零传动”又称直接驱动,即取消动力源与最终执行部件之间的所有机械传动环节。机床中常用的零传动功能部件有电主轴、直线电机和力矩电机等。零传动技术为提高机床性能提供了诸多好处:最大限度地减小了传动误差、为高速加工提供了可能、提高了机床执行部件的运动灵敏性等。目前,国外的先进滚齿机已大量采用了该项技术并取得了很好的成效,但其设计原理和技术均严格保密。为打破这种技术垄断局面,笔者所在课题组与国内某机床厂合作研发了一台基于零传动功能部件的数控滚齿机原型,并对相关理论和技术进行了比较系统的研究,其研究成果为提高我国齿轮加工机床的设计和制造水平打下基础。将零传动技术应用于滚齿机,不是单一针对零传动功能部件设计和制造技术的研究,也不是简单地将零传动功能部件置换进机床的工程处理过程,而是需要解决一系列从整体到局部的设计关键理论和技术问题。在这些问题中,既有滚齿机独有的问题,也有常规机床的共性问题。本文主要围绕零传动滚齿机精度控制理论和技术展开,并对机床的抗颤振结构优化问题进行了比较深入的探索。(1)对影响普通数控滚齿机展成运动精度的主要因素及其作用规律进行了分析,发现其展成运动误差仍然主要来自于机械传动环节,所以在原机床框架下进一步提高机床展成运动精度的空间不大;在此基础上,分析了零传动对提高展成运动精度的作用机理,研究结果表明:应用零传动技术在解决这一问题上具有先天的优势。因此,零传动滚齿机的精度控制重点,应当是机床两主轴之间的位姿精度和主轴部件的抗扰动能力。(2)实现机床精度的合理控制,建立一个有效的机床误差模型是必要的。根据滚齿机的结构和运动特点,机床的误差建模采用多体系统理论与齿轮啮合原理相结合的方法。该模型量化地描述了滚齿机各个组成部分之间的位姿和运动关系,尤其反映了各误差源对位姿、运动的作用规律和各误差源之间的关系,是机床精度控制工作的理论基础。(3)将加工误差敏感方向与机床误差源的传递规律相结合,提出了“机床敏感误差”(机床中对最终加工精度影响程度高的源误差)的概念,由此衍生出“敏感设计参数”和“误差敏感度”概念;以“抓主要矛盾”的思想,确定了针对机床敏感误差的机床精度控制策略。为实施机床的误差敏感度分析,以重构的方式将机床的理论误差模型简化为拥有两个子模型的工程误差模型,合理地将中间部件的位姿误差、运动误差参量与复杂的滚齿空间啮合关系分开,大大提高了模型的可操作性和使用的灵活性,同时使分析结果更具针对性。文中详细介绍了两个子模型的建立和使用方法,示例展示了其可行性和使用效果。(4)在分析综合国内外相关研究状况的基础上,以机床抗颤振结构优化为目的,对再生型切削颤振模型进行了系统的研究。根据研究结果,将机床加工系统简化为只具有两个弹性体的单自由度再生颤振模型,该模型能提高机床抗颤振结构优化的效率。基于此模型,一个“只对机床薄弱部件进行结构优化”的新构思被提出,并讨论了优化目标参数、数学模型和优化算法。试验研究结果展示了切削颤振产生和发展的过程和特征,同时验证了本文理论分析的正确性。以YK3610滚齿机样机的滚刀主轴系统为对象,对抗颤振结构优化的效果进行了模拟试验,取得了令人满意的结果。(5)介绍了YK3610样机的初步评估试验,试验数据反映了样机的主要性能,也揭示样机存在的一些问题,为该机床的调整和改进提供了第一手资料。更多还原

【Abstract】 “Zero-transmission”is also called“Direct-Drive”, namely all the mechanical transmission parts between motor and final executive component are canceled. In machine tool, the typical function components with Direct-Drive include“motorized spindle”, linear motor and internal torque motor. Zero-transmission technology provides many advantages for enhancing the machine tool performance, for example, maximally reducing the transmission error, offering the possibility of high-speed cutting, improving the movement sensitivity of the executive components, etc. Currently, this technology has been widely adopted in advanced hobber overseas, and has achieved good effect. However, all the interrelated design principles and technologies are kept as secret severely. In order to break this technology monopoly, cooperating with a Chinese machine tool company, the research group including the author has developed the No.1 CNC hobber prototype based on zero transmission function components in China, and many correlative theories and the technologies have been studied systematically in this process. These study results build a solid foundation for advancing the design and manufacture level of gear cutting machine of China.Applying the zero transmission technology in hobber is neither an onefold research on the zero transmission function components, nor a simple engineering process of replacing this type of function components into machine tool, but needs to solve a series of essential theory and the technical questions in design from whole to part. These problems include not only the particular one in hobber but also the general one in common machine tool. This article mainly discusses the strategies and methods of controlling the precision on a zero transmission hobber, and does some beneficial explorations on the anti-chatter structure optimization.(1) The main influential factors for generating motion precision and their action law are analyzed detailedly on a general CNC hobber, and the results show that the generating motion error also mainly comes from the mechanical transmission parts. Therefore, there’s not enough room to improve the generating motion precision under the existing machine frame. Based on it, the action mechanism that zero transmission improves the generating motion accuracy is studied. The study results show that zero transmission has natural dominance in solving this difficult problem. So the key points of the precision-control problem on the zero-transmission hobber should be to control the position-pose precision between the two spindles and improve the ability of anti-disturbance.(2) To realize the precision-control of a machine tool effectively, it is necessary to establish a valid error model of the object machine tool. According to the structure and the motion characteristics of the hobber, a theoretical model is built by combining the multi-body system theory with the gear meshing principle. This model describes the position-pose and motion relations quantitatively between the components in this hobber, and especially, contains the action rule of machine error sources and the relations between the error sources. It is the theory foundation for the precision-control work.(3) Combining the sensitive direction of processing error and the transmission law of source error, a new concept called“the sensitive error in machine tool”is put forward, which is a more influential source errors to final processing precision in the machine tool. According to the idea of fastening main factor, a new machine precision-control strategy to control the sensitive errors is proposed. To realize the sensitivity analysis of machine errors, the theoretical error model of the hobber is simplified to an engineering error model with two sub-models by reconstructing, which separates reasonably the numerous position-pose error parameters, the movement error parameters in middle components from the complex space meshing relation of gear hobbing. This model has the better operability, operational versatility and pertinence. In this paper, the details of how to build and use the two sub-models are introduced, and their feasibility and effect are demonstrated.(4) Based on analyzing and integrating the relative information coming from the domestic and oversea research and taking the anti-chatter structure improvement of machine tool as goal, the regenerative chatter model has been studied systematically. According to the study results, the machine processing system is simplified as a single-degree of freedom (SDOF) chatter model, which only has two elasticity bodies. The new model can make the anti-chatter structure improvement more effective. Based on this model, a new scheme is proposed, in which only the structure of weak component among a machine tool needs to be improved. Then, the optimizing target function, mathematical model and optimizing algorithm are discussed respectively. The experimental research results demonstrate the process and the characteristic during the cutting chatter occurring and expanding, and also the accuracy of relative theories are confirmed basically. Taking the hob spindle system of YK3610 hobber as an example, a simulation test has been done, and the result is satisfactory. (5) In the final part of this paper, some evaluation experiments of the YK3610 prototype at primary stage is introduced. The experiment data has reflected the main performance of this prototype, exposed some extant questions, and provided firsthand information to improve and adjust the machine tool.更多还原