【作者】 张帅；

【导师】 姜彬；

【作者基本信息】 哈尔滨理工大学 ， 机械工程（专业学位）， 2017， 硕士

【摘要】 大型螺纹类零件作为重型设备的关键调整组件,起着传递精度和扭矩的作用,大螺距螺纹加工表面形貌的优劣严重影响着整机设备的工作性能。螺纹件通常采用车削方式,但该类大螺距螺纹属于非标准件,尺寸大、螺距大、轴向长度长、加工余量大、牙型槽宽且深,加工过程中刀具刃口刃形保持性差,切削振动和磨损严重影响螺纹的耐磨性、密封性和使用寿命,破坏螺纹已加工表面形貌的一致性,因此,设计合理工艺方案,提高大螺距螺纹加工表面形貌一致性具有重要意义。本文来源于黑龙江省应用技术研究与开发计划项目“高品质大螺距螺纹高效切削技术”(GC13A404)及国家自然科学基金“基于广义动力学空间的高进给切削刀具振动磨损机理”(51575148);以提高大螺距螺纹加工表面形貌、实现大螺距螺纹加工表面形貌一致性为目标,针对企业中大螺距螺纹工件的工艺生产现状,进行车削大螺距螺纹加工表面形貌及其分布一致性的研究:针对大螺距螺纹轴向分层车削方式,建立车削大螺距螺纹刀具切削刃运动轨迹方程,分析刀具与工件接触关系,确定左右切削刃工作角度,提出车削大螺距螺纹加工表面形貌实验方案。结合大螺距外螺纹结构特点,提出加工表面形貌检测方法,依据左右螺纹面加工表面超景深检测结果和加工表面微观轮廓检测结果,采用加工表面不平度和加工表面粗糙度分布曲线,定量描述左右螺纹面加工表面形貌沿轴向的分布特性。针对大型螺纹类零件加工表面质量在机测量困难,研究切削刃磨损及刀具振动对加工表面形貌的影响,构建考虑刀具磨损和振动的大螺距螺纹加工表面形貌仿真模型,利用实验中获得的刀具和工件振动信号与切削刃磨损数据,进行大螺距螺纹加工表面形貌仿真,利用仿真实例与实验结果,验证加工表面形貌仿真模型的有效性。利用刀具磨损与振动测试结果,通过车削大螺距螺纹加工表面形貌仿真,分析左右螺纹面加工表面形貌随切削刃切削次数增加的变化特性,以螺纹面加工表面形貌分布均匀性和左右螺纹面加工表面形貌的相似度,评判刀具磨损与振动对加工表面形貌的影响,获取左右切削刃的最佳切削次数和切削行程;利用加工表面形貌沿轴向分布的仿真行为序列,采用绝对关联度表征和评价左右螺纹面加工表面形貌分布一致性,识别满足高加工表面质量要求的刀具磨损和振动特性及刀具使用寿命,为实现刀具磨损与切削振动的有效控制提供依据。针对大螺距螺杆车削工艺需求,利用工艺试切实验结果和加工表面形貌仿真模型,通过刀具磨损和振动对加工表面形貌影响的仿真与评判,确定工艺设计变量的可行域,以左右螺纹面加工表面形貌分布一致性为设计目标,提出车削大螺距螺纹精加工工艺设计方法,并进行车削工艺实验和加工表面形貌分布一致性分析与评判。结果表明,采用该方法获得的工艺方案,有效提高了加工表面形貌及其分布一致性。更多还原

【Abstract】 Large pitch thread plays an important role in the working performance of heavy-duty press as the key component transfer pressure and movement.The machined surface topography of large pitch thread directly determines its working performance.The thread parts are usually machined by turning,however,this kind of large pitch thread belongs to non-standard parts,and the tool cutting edge and the its shape have poor retention in the turning process because of large size,large pitch,long axial length,large machining allowance,and groove width and depth.The cutting vibration and wear seriously affect the wear resistance,the sealing property and the service life of thread,and even to destroy the consistency of the machined surface topography of thread.So,designing the reasonable process scheme and enhancing the consistency of machined surface topography of large pitch thread have great significance.This paper originates from the application technology research and development program of Heilongjiang province project "high quality efficient thread cutting technology"(GC13A404)and the National Natural Science Foundation "based on the generalized dynamic space gives high vibration cutting tool wear mechanism"(51575148);In order to improve the machined surface morphology of large pitch thread and to achieve its consistency,the machined surface morphology of large pitch thread and its consistency are studied according to the present situation of the production process of large pitch thread workpiece.Based on the characteristics of axial layering turning of large pitch thread,through establishing the movement trajectory equation of cutting edge analyzing contact relationship between the cutting tool and workpiece,then work angle between the left and right cutting edges are ensured and the machined surface morphology experimental plans of turning large pitch thread come forward.Combined with the structure characteristics of large external thread pitch,detection method of machined surface topography is proposed.According to the machined surface of super depth of field test results and micro contour detection results of the left and right thread surfaces,distribution characteristics along the axial direction of machined surface morphology can be quantitatively described by using the distribution curve of surface asperity and surface roughness.According to the fact that the machined surface quality of large type thread parts have difficulty on-machine measurement,the cutting edge wear and the effect of tool vibration on machining surface topography are studied.Under considering the tool wear and the vibration,the simulation model for machining surface topography of large pitch thread is established.By the tool and workpiece vibration signals and the cutting edge wear data obtaining from the experiment,the machining surface topography of large pitch thread is simulated,thereby proving the validity of simulation model using the simulation examples and experimental results.Firstly,based on the tool wear and the result of vibration experiment,according to the machined surface topography simulation of turning large pitch thread,the characteristics are analyzed,which belong to the machined surface topographies of left and right surfaces change with the increase of cutting times.Furthermore,the influence of tool wear and vibration to machined surface topography is judged by the distribution uniformity of machined surface topography and the similarity of different surface topographies in left and right thread surfaces,in addition,the best cutting times and cutting strokes of left and right cutting edges are obtained.Finally,according to the simulation behavior sequences of machined surface topographies in axial distribution and the absolute correlation degree,the distribution consistency belonging to the machined surface topographies of left and right surfaces is characterized and evaluated,the tool wear,the vibration characteristics and the service life which satisfies the high quality requirement of machined surface topography are identified.The above methods provide the basis of effectively controlling the tool wear and vibration.According to the turning process requirement of large pitch thread and using the trial cutting experimental result and the simulation model of machined surface topography,the feasible region of process design variables are determined by the simulation and evaluation of the tool wear and the effect of vibration on machined surface topography.Aiming at enhancing the distribution consistency of the machined surface topographies of left and right thread surfaces,the design method of finish machining process for turning large pitch thread is proposed.Finally,the turning experiment is carried out and the distribution consistency of the machined surface topography is analyzed and judged.The results show that the machined surface topography and its distribution consistency can be improved by adopting this method.更多还原