基于预定啮合特性的点啮合齿轮的CNC制造技术研究

CNC Manufacturing Technology of Point Meshing Gear Based on Predetermined Meshing Characteristics

针对当前螺旋锥齿轮技术不能充分利用数控机床的万能运动功能,保证点啮合齿面在整个传动过程中获得预定的啮合特性这一不足,论述经典齿轮啮合模型的一个反问题的数值解法:由给定加工刀具和加工目标齿面的几何结构确定加工刀具相对工件运动的齿面啮合问题的数值逼近方法——曲面的包络逼近原理。提出一种在Free-form型五轴联动数控机床上按预定齿面结构要求加工点啮合齿面的新方法,与以往介绍的加工方法不同,新方法加工的齿面与加工目标齿面沿预定的接触迹线具有二阶切触,完全满足设计所要求的预定的点啮合齿面的啮合特性,而在齿面的其他区域,该方法展成的齿面能以最小偏差逼近加工目标齿面。最后,以一个实例说明所提出方法的可行性和精确性。

In view of the deficiency of the current manufacture technique for the spiral bevel gears, in which the universal motion capability（UMC） of multi-axis simultaneous CNC bevel gear generating machines is unable to be utilized to generate point-meshing tooth surface with predetermined meshing characteristics in whole transmission process, a numerical solution to inverse geometry problem of classical meshing theory is discussed to solve the related motion of the workpiece and the rack-cutter based on the geometrical structure of tooth surface and the rack-cutter： surface-envelopment-approach principle. A new method for generating the meshing characteristic-oriented design of point-meshing tooth surface is presented by application of the five-axis simultaneous CNC cutting machine. Differing from previous studies, the new-process generated tooth surface coincides with the theoretical surface along the path of contact in tangency of second order and satisfies the meshing characteristic-oriented design of point-meshing tooth surface. In regions that differ from the path of contact, the new-process generated tooth surface can approach the theoretical surface with minimum deviation. An example is given to prove the feasibility and accuracy of the proposed method.