【作者】 张林；

【导师】 曹华军；

【作者基本信息】 重庆大学 ， 机械制造及其自动化， 2015， 硕士

【摘要】 高速干切滚刀是高速干式滚齿加工的关键装备之一,其结构复杂、生产制造成本昂贵。高速干式滚齿切削是一种复杂的多刃断续切削过程,在切削过程中滚刀承受复杂的高频冲击载荷,同时,由于切削加工缺少切削液的冷却和润滑作用,刀齿与工件产生剧烈摩擦、刀齿切削区温度较高。在复杂的机械载荷及热载荷的综合作用下,高速干切滚刀可能产生崩刃失效现象。高速干切滚刀崩刃失效是高速干切滚刀的主要失效形式之一,裂纹的萌生与扩展是高速干切滚刀崩刃失效的主要原因。崩刃失效直接降低滚刀寿命,并且严重影响齿轮加工质量和经济效益。目前,国内外对于高速干切滚刀裂纹扩展规律的研究尚不充分,针对高速干切滚刀崩刃失效开展高速干切滚刀裂纹扩展研究具有重要的意义。本文在国家863计划课题项目(2012AA040107)的资助下,采用了扩展有限元法对高速干切滚刀崩刃失效问题展开研究,具体研究工作如下:首先,本文在高速干切滚刀裂纹扩展的前提下,介绍了断裂力学及扩展有限元法(XFEM)的相关理论基础,其中,主要介绍了扩展有限元法、裂尖应力场及位移场、应力强度因子和断裂准则。其次,分析了高速干切滚刀生产制造工艺;归纳了传统刀具失效特征,并对传统刀具主要失效特征进行分析,在此基础上,分析了高速干切滚刀失效特征。然后,分析了高速干式滚齿运动关系,建立了高干切滚刀刀齿的几何模型,通过ABAQUS平台,开展了高速干切滚刀滚齿切削仿真。分析表明:高速干切滚刀在滚齿切削过程中刀齿侧刃和顶刃的应力值较大,容易萌生裂纹。最后,根据高速干切滚刀刀齿滚削应力云图,结合高速干切滚刀制造工艺及失效特征,确定了侧刃和顶刃的初始裂纹位置,建立了初始裂纹特征模型,通过ABAQUS平台采用XFEM对高速干切滚刀初始裂纹的扩展进行了仿真分析。分析结果表明:高速干切滚刀裂纹的扩展轨迹及扩展规律与裂纹的位置及参数有着密切的联系。更多还原

【Abstract】 High speed dry gear hobbing is one of the key technologies in high-speed dry hobbing. Its structure is complex and the manufacture is expensive. High-speed dry cutting hobbing is a complex multi-blade intermittent cutting process, gear hob is receiving high impact and complex loads. At the same time, due to the lack of cutting cooling and lubrication, the friction between cutter and workpiece is severe and the temperature of cutting zone is very high. Under the combined effect of the complex alternating mechanical load and thermal load, the tool may fail to produce chipping phenomenon.Chipping failure is one of the main failure modes in high-speed dry cutting hob. The main reason for chipping failure is the crack initiation and propagation in hob tooth and the chipping failure directly reduced the life of high speed dry cutting gear hob and it’s also seriously affects the quality and economic of gear hobbing processing. At present, carrying out research in this area is necessary, for the studies on high-speed dry cutting hob crack propagation are not sufficient.The paper is obtained by the support of 863 projects(2012AA040107). The high-speed dry cutting hob chipping is using by Extended Finite Element Method, the main contents are showed as follows:Firstly, the basic theory of fracture mechanics and XFEM are introduced for initial crack problem of high-speed dry hobbing. The crack tip stress field, displacement field, the stress intensity factor and fracture criterion are summarized, and its related equation is also derived.Secondly, the manufacturing process of high-speed dry cutting hob is analyzed and the characteristics of the traditional tool failures are summarized. At the same time, the failure characteristics of high-speed dry cutting hob are analyzed combined with the high-speed dry cutting hob process.Thirdly, the hob cutter geometry model is set up. High-speed dry hobbing movement is also determined. The high-speed dry hobbing simulation is implementing through the ABAQUS platform. The results showed that: the stress of side edge and the top edge are higher than the other place and it’s easy to initiation crack.Finally, the side edge and the top edge of initial crack model are set up by referring to the hob cutting stress cloud and the initial crack parameters. The crack propagation simulation analysis of high-speed dry hob is completed through the ABAQUS platform by using XFEM method. The results showed that: the crack growth track and regulation of high-speed dry hob are closely related to the location and parameters of cracks.更多还原