内啮合弧面凸轮机构压力角的计算方法

Pressure angle calculation method of internal meshing globoidal cam mechanism

弧面凸轮机构现有的外啮合形式结构尺寸较大,分度数有限,为此提出内啮合弧面凸轮机构。通过空间曲面啮合原理,结合回转变换张量得到了内啮合弧面凸轮机构压力角的计算方法,并通过分析计算寻找压力角的影响因素。结果表明中心距、凸轮基圆半径、从动件运动规律对机构压力角影响较大,从动盘回转半径、滚子形状和尺寸、啮合点位置变化对压力角影响较小;并且中心距越小,基圆半径越大,压力角越小。通过实例验证,减小中心距和改变从动件运动规律,机构压力角会明显减小,这一结果说明在满足传力性能的同时,内啮合弧面凸轮机构结构更加紧凑,为拓展弧面凸轮机构的应用领域提供了理论依据。

The outer meshing globoidal cam mechanism has a large structure size and a limited index number.Therefore,an internal meshing globoidal cam mechanism was proposed.Based on the meshing principle of spatial curved surface and in combination with the rotation transformation tensor,the calculation method of pressure angle of internal meshing globoidal cam mechanism was obtained,and the influencing factors of pressure angle were found through analysis and calculation.The results show that the center distance,cam base circle radius and follower motion law have great influence on the pressure angle of the mechanism,while the rotation radius of the driven plate,the shape and size of the roller and the position of the meshing point have little influence on the pressure angle;and the smaller the center distance,the larger the base circle radius and the smaller the pressure angle.It was verified through examples that,when reducing the center distance and changing the motion law of the follower,the pressure angle of the mechanism will be reduced obviously.This result shows that the internal meshing globoidal cam mechanism has more compact structure while meeting the force transmission performance,which provides a theoretical basis for expanding the application field of globoidal cam mechanism.