【作者】 刘静；

【导师】 丛明；

【作者基本信息】 大连理工大学 ， 机械制造及其自动化， 2008， 硕士

【摘要】 高速加工中心是高速机床的典型产品,高速功能部件的发展与应用极大地提高了切削效率。随着切削时间的缩短,对换刀时间的要求也逐步提高,换刀速度已成为高水平加工中心的一项重要指标。自动换刀系统必须工作可靠准确,结构又相对复杂,提高换刀速度的技术难度大。因此,自动换刀技术成为机床制造业竞争的焦点之一。本文在充分调研国内外自动换刀技术发展及其研究现状的基础上,对各类刀库和刀具交换机构进行了探讨和比较,研究双凸轮联动自动换刀技术,分析双凸轮联动自动换刀机构的优点和结构特点,并结合MDH卧式加工中心对双凸轮联动自动换刀装置进行结构设计和工作原理分析。设计双凸轮联动结构,双凸轮是指驱动刀具松拉杆运动的盘形凸轮和驱动机械手运动的复合凸轮(包括弧面分度凸轮及镶嵌在其侧面的沟槽凸轮)。文中主要完成了对两套(三个)凸轮运动循环图的匹配设计,凸轮机构运动规律的分析选择,主要采用修正正弦曲线和修正等速曲线运动规律。对弧面分度凸轮三维建模方法进行研究分析,基于逆向思维推导出一种对弧面分度凸轮精确建模的方法。根据弧面分度凸轮的理论轮廓曲面方程,结合分度盘运动规律可在凸轮毛坯模型上建立理论轮廓曲面,对其进行法向偏置、实体切除操作得到工作轮廓曲面,修整后获得精确的凸轮模型。基于Pro/E软件,给出了用于MDH卧式加工中心自动换刀装置中的多头复杂弧面分度凸轮的建模实例,模型精度满足设计要求,验证了该方法的正确性和可行性。创建基于MDH卧式加工中心的双凸轮联动自动换刀装置虚拟样机,进行运动仿真分析,得到刀具松拉杆直线运动、换刀机械手直线运动和旋转运动的位移、速度和加速度曲线图,仿真测量结果符合设计要求。最后,总结分析了双凸轮联动自动换刀技术在实际应用过程中存在的问题和不足,对下一步研究工作提出了展望。更多还原

【Abstract】 High-speed machining center is a typical product in high-speed machine tool. The development application of high-speed features has greatly improved the efficiency of cutting. With the shortening of cutting time, it is required to reduce tool change time. The speed of tool change has become an important indicator of high level machining center. Automatic tool change system, with relatively complex structure, must work accurately and reliably. It’s difficult to increase the tool change speed. So automatic tool change technology has become one of the competitive focal points in machine tool manufacturing.Based on the study of domestic and foreign research and development about automatic tool change technology, the various types of tool magazine and tool exchange structure are discussed and compared. Dual-cam linkage automatic tool change techonoly is studied. The advantages and structural characteristics of dual-cam linkage mechanism are presented. With MDH horizontal machining center, the structural design and working principle of dual-cam linkage ATC are analyzed.Design the dual-cam linkage structure. Dual-cam includes a plate cam controlling tool bar movement and a composite cam (a slot cam inlaid on one side of a globoidal cam) controlling manipulator movement. The motion cycle chart of two sets of (three) cams is designed. The motion law of cam mechanisms is discussed, and modified sine (MS) curve and modified constant velocity (MCV) curve are chosen.A three-dimensional modeling method of globoidal cam is presented. Based on converse thinking, a modeling method is proposed. Theoretical profiles are built up on the blank model of globoidal cam combined with theoretical profile equations and movement laws, and working profiles are obtained by normal offset of the theoretical profiles and solid cutting operation. The accurate model of globoidal cam is completed after modification. A modeling example of the complex multi-head globoidal cam used in ATC of MDH horizontal machining center is carried out in Pro/E, and kinematics simulation is carried out. The result meet the design requirements, showing validity and feasibility of the method.Based on MDH horizontal machining center, the virtual prototyping of dual-cam linkage ATC is created, and simulation analysis is carried out. The displacement, velocity and acceleration measurements of linear motion of tool bar, linear motion and rotation movement of ATC manipulator match with the cam motion cycle chart and cam motion law design. At last, the problems of dual-cam linkage automatic tool change technology in practical application process are summarized, and recommendations and prospects are presented for the further work.更多还原