后刀面对数螺旋曲面的逼近方法和实现机构

Approximation Method of Logarithmic Spiral Used as Tool Flank Surface and Realization Mechanism

在金属切削成型刀具中,刀具后角对切削性能的影响至关重要,通常设计和使用最优后角值。但以阿基米德螺旋面为后刀面、重磨前刀面的成型刀具一旦发生磨损重磨,后角值便会偏离原有理想值,直接影响切削效果和刀具使用寿命。本文提出了一种以逼近对数螺旋面为工作后刀面的设计方案,无论重磨多少次,刀具后角均始终保持原理想值。设计了相应的实现机构并进行了误差分析,结果表明,以逼近对数螺旋面为工作后刀面可以保证刀具合理后角且不发生变形,逼近误差在可接受范围内。

In metal cutting forming tools,the influence of tool back angle on cutting performance is very important.The optimal back angle value is usually designed and used.However,when the Archimedean spiral surface is used as the flank or the regrinding rake surface,the flank angle deviates from the original ideal value once it is worn and regrinding,which directly affects the cutting effect and tool service life.This paper presents a design scheme taking the approximate logarithmic helicoid as the working flank.The tool flank angle always keeps the original ideal value,no matter the times of regrinding of the tool rake.The corresponding implementation mechanism is given and the error analysis is carried out.The results show that the use of the approximate logarithmic helicoid as the working flank can ensure the optimal clearance angle keeping from deformation,and the approximation error is within the acceptable range.