【作者】 肖思来；

【导师】 周志雄；

【作者基本信息】 湖南大学 ， 机械制造及其自动化， 2013， 博士

【摘要】 深孔加工在通用机械、汽车制造、航空航天、国防、石油、矿山、农业机械和工程机械等诸多领域有着广泛的应用。深孔加工是一种半封闭的加工方式，具有切削热难以散发，排屑困难，工艺系统刚性差，切削效果不理想等特点，被认为是最难的金属切削问题之一。由于深孔钻削技术难度大，在低端市场，国内用户一般使用抛物线型深孔麻花钻，而且采用分级进给方式进行加工，效率很低；而深孔加工领域的高端市场一直被国外厂商占领。随着国内机械制造业的不断发展，刀具技术的不断成熟，一些关系到国家经济命脉的关键性领域，特别是汽车制造业，对自主开发国产高档深孔麻花钻的呼声越来越高。本文通过理论研究、数值仿真以及试验研究等手段，对深孔加工麻花钻的螺旋槽槽型及钻尖型式进行优化，提出了变参数螺旋槽平面后刀面型深孔麻花钻结构设计的思路，并对新型深孔钻的失效机理和切削力模型进行了研究。本文的主要研究内容有：（1）对变参数螺旋槽深孔麻花钻的数学模型及精确三维建模方法进行了研究。通过对深孔钻削机理的研究，提出了变参数螺旋槽结构型式。应用无瞬心包络原理，分析了砂轮加工变参数螺旋槽的运动过程，推导出了变参数螺旋槽深孔麻花钻的数学模型，并从理论上证明了新型深孔麻花钻的结构特点。基于B样条曲面插值算法，在UG中建立了变参数螺旋槽的三维实体模型，验证了模型的精确性。（2）对变参数螺旋槽深孔麻花钻进行了结构优化设计。基于变参数螺旋槽的特性，设计了螺旋槽的横截面形状。将正交试验设计方法与数值仿真手段相结合，对钻尖关键结构参数进行了优选和改进，并进行了实验验证，确定了变参数螺旋槽结构深孔麻花钻的关键钻尖结构参数。（3）从钻削力、被加工孔表面质量及刀具失效形式三方面探讨了深孔钻削机理。通过切削力对比实验论证了新型深孔麻花钻的变参数螺旋槽结构，有助于减小深孔加工的钻削力，提高麻花钻钻削稳定性。通过孔粗糙度和孔径扩大量测试，讨论了切削参数和芯厚增量对两者的影响。通过灰口铸铁、球磨铸铁和合金钢等材料的耐磨损实验研究，初步探讨新型深孔麻花钻的失效机理。（4）通过正交钻削实验设计，采集了不同钻削实验方案的钻削力数据，建立了变参数螺旋槽深孔麻花钻钻削45钢和LC4铝合金的钻削力数学模型，试验验证了切削力数学模型的可靠性。通过修正系数的方法建立了LC4铝合金基于45钢的钻削力数学模型，并验证了修正系数方法的可靠性。用同样的方法推导出了HT300和42CrMo基于45钢的切削力数学模型，分析了加工不同材料时钻削力相对于加工45钢钻削力的差异。更多还原

【Abstract】 Deep-hole machining has been widely used in various areas such as aerospace,automobile manufacturing, national defense, general machinery, petroleum, miningenterprises, agricultural machinery and engineering machinery. Deep hole drillingprocess is conducted in closed or semi-closed situations, which brings about the mostdifficult problems of metal cutting, such as difficulty in scattering the heat in metalcutting and clearing the cutting chips, poor rigidity of the metal cutting operation system,and unsatisfactory cutting effects. Due to technical difficulties of deep-hole drilling, inthe low-end market, domestic users generally use parabolic type deep-hole drill, andapply the graded feeding mode, so the drilling efficiency is very low; while the high-endmarket has been occupied by foreign firms. With the continuous development of thedomestic machinery manufacturing and tool technology, the voice of independentlydeveloping home-made high-grade deep hole twist drill is louder and louder, in the keyareas of pillar of the national economy, especially in the automobile manufacturingindustry.In this dissertation, optimization of the spiral groove and the forms of drill pointwas carried out, and a structural design method for the new type of deep-hole twist drillwith variable parameters spiral groove and plane flank was put forward by means oftheoretical research, numerical simulation and experimental research. Then the failuremechanism and the cutting force model of deep hole drilling were studied. The mainwork is as follows:(1) The mathematical model of a new type of deep hole twist drill with variableparameters spiral groove and precise3D modeling method were studied. Through theinvestigation of cutting mechanism of the deep hole drilling, the structure of variableparameters spiral groove was designed. Application of non-instantaneous pole envelopeprinciple, the movement process of the grinding wheels’ processing variable parameterspiral groove was analyzed, and the mathematic model of the deep-hole twist drill withvariable parameters spiral groove was set up. And then the structural characteristics ofthe new type of deep hole twist drill was theoretically proved. Based on the algorithm ofB spline surface interpolation, the method of establishing the3-D solid model of thevariable parameter spiral groove was found by applying UG, and the accuracy of3-Dmodel was verified. (2) Optimization for the structure of a new type of deep hole twist drill withvariable parameters spiral groove was carried out. Based on the characteristics ofvariable parameters spiral groove, the shape of cross section of the spiral groove wasdesigned. Through combining the orthogonal test design method with numericalsimulation method, key structure parameters of drill point were optimized and improved,and the best design was verified and determined by experiment.(3) The deep hole drilling mechanism was discussed from the aspects of drillingforce, the machining quality of hole surface and tool failure type. Firstly，by contrastexperiments, that variable parameters spiral groove structure of the new type ofdeep-hole twist drill could decrease cutting force and improve drilling stability wereproved. Secondly, through the hole roughness and aperture expansion test, the influenceof cutting parameters and the core thickness increment on the two was discussed. Thirdly,through the experimental research on the wear resistance of the new type of deep-holetwist drill in machining gray cast iron, nodular cast iron and alloy steel and othermaterials, the failure mechanism was preliminarily studied.(4) By using the method of orthogonal experiment, and using the cutting force datacollected in different drilling experiment scheme, the drilling force mathematical modelof the new type of deep-hole twist drill with variable parameters spiral groove cutting45steel and LC4aluminum alloy was established, and then its reliability was verified. Bythe methods of correction coefficient, the cutting force mathematical model of LC4basedon the cutting force of45steel was established and then verified, which proved thereliability of the method of correction coefficient. Through the same methods, the cuttingforce mathematical models of HT300and42CrMo were obtained, and the differencebetween cutting force in drilling different materials and that in drilling45steel wasanalysed.更多还原