Generating CBN Grinding of 3 Dimensional Curved Surface of Machine Parts

在展成磨削时的磨削速度和进给速度，例如在齿轮齿面的展成磨削的情况下，不能独立选择，并且磨削速度的绝对值通常很慢。这与传统的外圆磨削有很大的不同。用盘式CBN磨床在慢速磨削条件下对渗层硬化试件进行了基础磨削试验，结果表明：(1)恒磨距磨削量与磨削速度无关；(2)与磨削压力成正比；(3)随轧制速度增加，磨削量增大。试验中发现CBN磨床存在三种失效形式：(1)试件划伤导致镍结失效，(2)试件材料覆盖CBN晶体，(3)脉冲高接触压力导致CBN晶体断裂。根据上述恒压低速CBN磨削的基本原理，开发了CBN砂轮齿面磨削仿真程序。仿真结果显示了CBN磨床在运行过程中的压力分布和加工齿轮的齿面形状精度。这些结果可以作为砂轮尺寸和形状精度以及磨削操作条件的函数得到。仿真结果表明，磨削过程中设置高进给量或大磨削压力会导致齿形精度下降。将仿真结果与CBN磨齿机的仿真结果进行了比较，并对结果进行了讨论。

The grinding velocity and feeding velocity at generating grinding, for instance in the case of generating grinding of gear tooth flanks, cannot be selected independently and the absolute value of grinding velocity is in general very slow. This is a big difference from the conventional grinding such as cylindrical grinding. The basic grinding test of case hardened specimen under constant pressure using disk type CBN grinder under slow grinding speed reveals, that the amount of removal by constant grinding distance is (1) independent from the grinding velocity, (2) proportional to the grinding pressure and (3) it increases with increasing rolling velocity. Three kinds of failure of CBN grinder were found during the test : (1) Failure of Nickel Bond by scratching of specimen, (2) Covering of CBN crystal by the material of specimen and (3) fracture of CBN crystal due to high contact pressure of impulse.The simulation program of tooth flank grinding using CBN grinder of gear wheel shape was developed using the results of the fundamental nature of constant pressure and slow speed CBN grinding mentioned above. The simulation shows the pressure distribution which acts on the CBN grinder during operation and the form accuracy of tooth flank of manufactured gear. These results can be obtained as functions of dimensions and form accuracy of grinding wheel and of operating condition of grinding. The results of the simulation show that the setting of high-feed or of large grinding pressure at the operation of grinding induces the deterioration of tooth form accuracy. The results were discussed by comparing the results of simulation and those of CBN ground gear using Hurt-type gear grinder.