滚切加工作为当前圆柱齿轮制造应用最为广泛的工艺具有高效但成形过程复杂的特点。基于展成原理,由规则分布在滚刀基本蜗杆螺旋面上的一系列切削刃相继从圆柱齿坯上切除材料,最终包络形成渐开线齿面。研究其成形原理可以为提升该工艺性能提供有效指导。针对齿轮滚切工艺过程多刃切削成形特征,建立圆柱齿轮滚切的空间成形模型。基于滚刀几何结构参数的理论约束关系,建立滚刀切削刃序列的参数方程;根据滚刀和工件的几何参数以及切削参数确定滚切过程中滚刀与工件的空间位置和运动关系,并基于空间运动学方法推导求得滚刀刀刃序列形成的空间成形曲面参数模型;采用离散数值方法获得滚切过程中的切屑几何形态及切屑厚度,并根据切屑几何计算各刀刃去除材料时的瞬时主切削力。该模型可以为滚切工艺参数优化、滚刀几何设计等研究提供支撑。
As the most widely used cylindrical gear machining approach, gear hobbing owns characteristics of high efficiency but complexity. On the basis of generating theory, a series of cutting edges which regularly distributed on the basic worm face of the hob is going to remove material from the gear blank successively and the involute tooth flank is shaped by enveloping. The study on its forming principle can provide effective guidance for performance improvement. In allusion to the characteristics of multi-edge cutting, the spatial forming model for cylindrical gear hobbing is established. The parametric equation of cutting edges sequence is established based on the theoretical constraint relationship of the geometrical and structural parameters of the hob. The kinematics relationship between the hob and gear blank is determined according to geometric parameters of hob and gear as well as machining parameters. The parametric model of the spatial forming surface generated by the cutting edge sequence is derived. Based on the model, the geometry and thickness of the chip corresponding to each cutting edge is obtained with numerical method by discretization. And the dynamic main cutting force in gear hobbing process is calculated according to the chip geometry. The established model can be utilized to support parameter optimization of gear hobbing process and the geometric design of hob.