基于样条函数的配气凸轮曲线设计

Profile Design of Inlet/Exhaust Cam Using the Spline Method

基于δ—三次样条函数方法,研究了配气凸轮曲线的拟合及其误差范围。将复杂的凸轮曲线用一个连续函数表示,而不必事先假定凸轮曲线的类型,并可通过适当调整三次样条函数的系数Cj 改善曲线形状以适应额外的内点和边界条件。曲线拟合精度可通过增加插值节点进一步提高而不会改变拟合公式的统一性,结果表明曲线设计灵活性和适应性较大,对各类凸轮曲线的设计都具有实用价值。

Based on the δ-cubic spline method, the profile fitting of inlet/exhaust cam and its error range are studied in this paper. The complicated cam profile can be expressed by one continuous function while not postulating the types of cam curves in advance. Moreover, the cam profile can be changed through adjusting the coefficient Cj of the cubic spline function properly to satisfy additional interior and boundary conditions. Adding more interpolation nodes can improve the fitting precision of the cam profile yet the unitarity of the fitting function will keep unchanged. The result shows that the method has practical importance for the design of various cam profiles with better flexibility and adaptability.