轻薄轴承超高速离心式无心磨削及表面残余应力形成机理研究

The project proposes the set of center-less grinding and centrifugal grinding as one of the new method for ultra-high speed grinding ultracentrifuge center-less grinding processing thin bearing ring. The proposed project will overcome the drawback of the poor rigidity, easy deformation and beating of bearing rings. The centrifugal effect of the high-speed rotation of work piece can improve the ferrule dynamic processing stiffness, gyroscopic stability, and pre-load can also be applied to form pre-stressing for the work piece.This projects focus on the research of centrifugal effect, gyroscopic effect, pre-deformation effect of the coupling relations as well as the surface of many parameters of the centrifugal force, pre-stressed, grinding force, grinding heat in the pre-stressing effect of ultra high-speed centrifugal center-less grinding strengthening layer metamorphic layer, residual stress formation and control mechanism; clarify the relationship between process parameters and their influence factors on the processing quality (including size and shape accuracy, surface roughness, waviness, geometric accuracy and surface mechanical and physical properties).Experiments will be conducted to identify and analyze the surface residual stress distribution, a reasonable process parameters will also be determined by orthogonal experiments. Thorough investigation will be conducted to analyze the hardened layer, microstructure, surface morphology of the degree of geometric precision to observe whether the work piece surface will produce adsorbed film, over cold hardening layer and white layer of black spots. This research project will advance the processing technology and its theoretical development, and strive to bring a breakthrough in the theory and methods on the thin bearing processing in China.

针对轻薄轴承套圈加工刚性差、易变形和跳动的特点，项目提出集无心磨削、离心磨削为一体的超高速磨削加工新方法"超高速离心式无心磨削"加工轻薄轴承套圈。工件高速旋转的离心效应可提高套圈的动态加工刚度、陀螺稳定性，并可对工件施加预载荷形成预应力。项目研究基于"离心效应、陀螺效应、预变形效应、预应力效应"的超高速离心式无心磨削加工中离心力、预应力、磨削力、磨削热等诸多参数的耦合关系以及表面强化层、变质层、残余应力形成与控制机理；弄清工艺参数之间的关系及其对加工质量（包括尺寸和形状精度、表面粗糙度、波纹度等几何精度与表面机械物理性能）影响因素；实验测定并分析表面残余应力分布，通过正交实验确定合理工艺参数，分析硬化层、金相组织、表面微观形貌度、几何精度等的影响，观察工件表面是否生产吸附膜、过冷作硬化层、白层、小黑点等；研究工作将促进加工技术及其相关理论发展，力求为我国轻薄轴承加工在理论和方法上带来突破。

针对轻薄轴承套圈加工刚性差、易变形和跳动的特点，项目提出集无心磨削、离心磨削为一体的超高速磨削加工新方法“超高速离心式无心磨削”加工轻薄轴承套圈。工件高速旋转的离心效应可提高套圈的动态加工刚度、陀螺稳定性，并可对工件施加预载荷形成预应力。项目研究基于“离心效应、陀螺效应、预变形效应、预应力效应”的超高速离心式无心磨削加工中离心力、预应力、磨削力、磨削热等诸多参数的耦合关系以及表面强化层、变质层、残余应力形成与控制机理；弄清工艺参数之间的关系及其对加工质量影响因素；实验测定并分析表面残余应力分布，通过正交实验确定合理工艺参数，分析硬化层、金相组织、表面微观形貌度、几何精度等的影响。研究结果表明：超高速磨削加工中，磨削力随着砂轮线速度的增加而减小，但随着磨削深度增加而增加；超高速磨削加工后工件表面平滑，存在少量小白点及烧伤区域，残余压应力达到-100~-170MPa。研究工作将促进加工技术及其相关理论发展，力求为我国轻薄轴承加工在理论和方法上带来突破。