Generating CBN Grinding of 3 Dimensional Curved Surface of Machine Parts

产生磨削时的磨削速度和进给速度不能独立选择，例如齿侧的产生磨削时，磨削速度的绝对值一般很慢。这与传统的外圆磨削有很大的不同。用圆盘式CBN磨床在慢磨削速度下对壳体硬化试样进行恒压基本磨削试验，结果表明：恒磨削距离的去除量与磨削速度无关，与磨削压力成正比，且随轧制速度的增加而增加。试验中发现CBN磨床有三种失效类型：(1)试样划伤导致镍键破坏；(2)试样材料覆盖CBN晶体；(3)冲击接触压力过大导致CBN晶体断裂。利用上述恒压慢速CBN磨削的基本性质，开发了CBN磨床磨削齿轮形齿面的仿真程序。仿真结果显示了CBN磨床在工作过程中的压力分布及所制齿轮齿面形状精度。这些结果是砂轮尺寸、形状精度和磨削操作条件的函数。仿真结果表明，磨削时大进给量或大磨削压力的设置会导致齿形精度的下降。并将仿真结果与使用赫特型磨床的CBN磨削齿轮的仿真结果进行了比较。

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.