The Design And Manufacturing Of Conical Spiral Tooth Grinding Wheel Based On The Curve Conjugate Principle

Internal gear is widely used in planetary gear trains such as automobile automatic transmission and robot reducer.In order to improve the bearing capacity of internal gear,heat treatment is necessary to improve the hardness of tooth surface,but thin-walled internal gear is prone to thermal deformation during heat treatment,furthermore,the direction of thermal deformation is unpredictable.Thermal deformation will reduce the accuracy of internal gear,which does not meet the increasing requirement of low noise,low vibration and high accuracy for automobiles and robots,so it is necessary to finish the internal gear after heat treatment.However,the hard tooth surface after heat treatment is difficult to be machined.Even though the traditional gear form grinding can machine the hard tooth surface of internal gear,the efficiency and cost can not meet the mass production in automobile and robot industries.It is necessary to develop a new machining method and technology for hard tooth surface of internal gear.In view of the above problems,based on the theory of curve conjugation,a conical spiral tooth grinding wheel is proposed,which can be used for continuous indexing grinding of inner gear ring.When grinding,with the increase of feed,the back feed of the grinding wheel increases gradually,and the whole inner gear ring can be machined by one-time feed.This method can solve the problem that the inner gear ring can not be machined because of its small diameter leading to interference,and also improve the processing efficiency.Firstly,the cutting principle of conical spiral tooth grinding wheel is analyzed.Since there is always relative velocity at the contact point between the grinding wheel and the workpiece in the process of synchronous movement,abrasive particles on grinding wheel remove material of workpiece.Then,the forming principle of the workpiece's tooth surface are deeply studied with the theory of curve conjugation,and the mathematical model of the conical spiral tooth grinding wheel's tooth surface is deduced.Taking an typical inner gear ring as an example,the influence of relevant parameters on the design of conical spiral tooth grinding wheel is analyzed,and the corresponding selection basis are given.The simulation processing of inner gear ring grinding by simulation processing software verifies the rationality of tool design.The technological path of grinding wheel manufacturing is formulated,and the grinding wheel matrix is processed by a five-axis CNC tool grinder.Finally,the grinding experiment of inner ring gear is carried out,and the experimental results show that gear grinding principle and design method of grinding wheel for conical spiral tooth grinding wheel is feasible.