楔式动力卡盘定心精度与夹紧力特性研究

发布时间：2018-07-17 07:54

【摘要】：高速切削加工技术具有加工效率高,切削力小,表面质量好的优点,被公认为是面向二十一世纪的先进加工技术。而卡盘是现代机床加工回转型的零件的关键夹具,被广泛应用。液压动力卡盘由于其具有高转速、夹紧力大、结构紧凑等优点,而被广泛应用于中速及高速数控车床、数控车铣中心和数控磨床等加工技术中。但是卡盘在高速运转下由于卡爪的质量大导致卡盘的离心力作用使动态夹紧力损失,限制了液压动力卡盘高转速的提升。另外,动力卡盘的夹持精度也是制约数控机床精度提高的关键因素之一。本文主要对卡盘的定心精度和夹紧力进行了研究。首先,在清华大学夹持精度已有研究的基础上,针对卡盘盘体和楔心套在装配过程中存在的装配间隙过大或过小,装配精度差的问题,根据分组互换法原理提出了分组互换装配法,并通过实验进行了验证。对比实验结果和已有理论分析,证明提出的分组互换装配法对卡盘的定心精度有着很大的提高。其次,对卡盘夹紧力进行研究。在实验的基础上以良好的楔式动力卡盘为研究对象,在内蒙古众环油缸综合试验机上对卡盘进行摩擦磨损实验,研究了卡盘夹紧力随重复夹紧次数的变化规律。并利用扫描电镜(SEM)和能谱分析仪(EDS)等现代仪器对卡盘主要摩擦表面的表面形貌进行了观察分析,探究了卡盘摩擦副的磨损机理,得出卡盘摩擦磨损主要以氧化磨损和磨粒磨损为主,黏着磨损为辅的情况。并对卡盘的设计和使用提出指导意见。采用有限元分析的方法对影响卡盘夹紧力的因素进行了分析,并进行了仿真,获得了卡盘摩擦系数、使用参数和卡爪材料等对卡盘夹紧力的影响规律。文章详细的描述了有限元仿真的过程。最后通过实验的方法对卡盘动态夹紧力与转速的关系进行研究。并利用ANSYS的二次开发功能,初步开发了卡盘参数有限元仿真系统。本文以KT55-200楔式卡盘为例,说明参数化模块开发的过程。
[Abstract]:High speed cutting technology has the advantages of high machining efficiency, low cutting force and good surface quality. It is recognized as an advanced machining technology facing the 21 century. Chuck is the key fixture of modern machine tool. Hydraulic power chuck has been widely used in machining technology such as medium speed and high speed CNC lathe, CNC turn-milling center and CNC grinder because of its advantages of high speed, high clamping force and compact structure. However, the centrifugal force of the chuck can lose the dynamic clamping force due to the high quality of the chuck at high speed, which limits the increase of the high speed of the hydraulic power chuck. In addition, the clamping accuracy of power chuck is also one of the key factors restricting the improvement of NC machine accuracy. In this paper, the centering accuracy and clamping force of chuck are studied. First of all, on the basis of the existing research on the clamping accuracy of Tsinghua University, the problems of too large or too small assembly clearance and poor assembly accuracy exist in the assembly process of the chuck disk body and the wedge core sleeve. According to the principle of grouping exchange, a grouping exchange assembly method is proposed and verified by experiments. Compared with the experimental results and theoretical analysis, it is proved that the proposed grouping exchange assembly method can greatly improve the accuracy of chuck centering. Secondly, the chuck clamping force is studied. On the basis of the experiment, the friction and wear experiments of the chuck were carried out on the inner Mongolia multi-ring oil cylinder comprehensive testing machine with a good wedge power chuck, and the variation law of the chuck clamping force with the repeated clamping times was studied. The surface morphology of the main friction surface of the chuck was observed and analyzed by using modern instruments such as scanning electron microscope (SEM) and energy dispersive analyzer (EDS), and the wear mechanism of the chuck friction pair was explored. The results show that the friction and wear of chuck are mainly oxidation wear and abrasive wear, and adhesion wear is secondary. And to the chuck design and use of the guidance. The factors affecting the chuck clamping force are analyzed by finite element analysis. The friction coefficient of the chuck, the parameters of the chuck and the clawing material, etc., are obtained by simulation, and the law of influence on the chuck clamping force is obtained. This paper describes the process of finite element simulation in detail. Finally, the relationship between dynamic clamping force and rotational speed of chuck is studied by experimental method. The finite element simulation system of chuck parameters is developed by using the secondary development function of ANSYS. Taking KT 55-200 wedge chuck as an example, this paper explains the development process of parameterized module.
【学位授予单位】：烟台大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TG75
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本文编号：2129685