Generating CBN Grinding of 3 Dimensional Curved Surface of Machine Parts

在展成磨削时，例如在齿轮齿面的展成磨削的情况下，不能独立地选择磨削速度和进给速度，并且磨削速度的绝对值通常非常低。这与传统的磨削如外圆磨削有很大的不同。用圆盘式CBN砂轮机在低速恒压磨削条件下对表面硬化试样进行了基本磨削试验，结果表明：恒距磨削去除量与磨削速度无关，与磨削压力成正比，随磨削速度的增加而增加。在试验过程中发现CBN砂轮机的三种故障：（1）试样划伤导致镍结合失效，（2）CBN晶体被试样的材料覆盖，以及（3）利用脉冲冲击的恒压和慢压的基本性质，开发了齿轮型CBN砂轮磨削齿面的仿真程序，高速CBN磨削。仿真结果显示了CBN砂轮工作过程中的压力分布和所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工况的函数得到。仿真结果表明，高进给量或大磨削压力的设置会导致齿形精度的恶化。通过仿真结果与用赫特式磨齿机磨削CBN齿轮的结果进行比较，对仿真结果进行了讨论。

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.