| In automata and automatic lines, in order to meet the requirements of production process, we need to use intermittent indexing mechanism to achieve the transposition of the cyclical movement and step movement. Because of good movement characteristics, high repetition accuracy, smooth movement and other characteristics, intermittent indexing cam mechanism is widely used in variety of automata and automatic lines.Intermittent cam indexing mechanism can be divided into three types based on it's structure, parallel indexing cam mechanism, cylinder indexing cam mechanism and globoidal indexing cam mechanism. The structures of these intermittent cam indexing mechanisms are similar, mainly assembled of the cam and the rotating plate with some rollers, which intermittent revolves by the promotion of the cam. The continuous rotation of the cam is converted to intermittent rotation of the indexing, and the movement of the mechanism is in accordance with predetermined cam curve.This paper studies the cam curve at first. The merits of the cam curve directly impact on intermittent indexing cam mechanism's performance. This paper discusses several commonly cam curves and respectively calculates the displacement, velocity, acceleration, jerk and jump equation. By analyzing the characteristics of these curves, some cam curve's selection criterias are concluded. Then this paper researches the profile surface equation of the intermittent indexing cam. Based on the established the kinematic model of intermittent indexing cam mechanism, by using two-dimensional and space mesh theory complex vector equation, space tensor transformation and the other mathematics knowledges, the equation of the intermittent indexing cam profile surface is derived.Based on the above research, visual software was designed by using VC++ programming and OpenGL graphics library, and the cloud points of intermittent cam surface contour are achieved. Then the solid model of the cam and the entire assembled model are designed by the UG4.0 software, and the intermittent indexing cam mechanism's kinematic simulation model is established by the motion simulation software, and analyzing the movement of mechanism and inspecting the interference among the process of the movement. Finally, this paper discusses on the machining problems of intermittent indexing cam's profile surface. According to the characteristics of the three kinds of intermittent indexing cams, each machining method of cam profile and the generation of tool trajectories are listed by three-dimensional machining software. |
