Meshing Analysis of the Planetary Indexing Cam Mechanisms

Abstract

The planetary indexing cam mechanism is a type of indexing cam mechanism that employs planetary transmission structure. The mechanism is unusual compared to other planar cam mechanisms for the self-intersection occurs inevitably on the pitch curve of the cam. This results in the loss of contacts between a few rollers and cam profile. This paper investigates the effects of such loss of contacts on the transmission by analyzing the meshing procedure of the mechanism. The number of the self-intersection points on the pitch curve is determined in terms of the rotary index of the continuous curve. The meshing procedure is analyzed in detail and the pressure angles are calculated. The effects of the design parameters on the meshing status are studied and illustrated. At the end, it is pointed out that loss of contacts will not hamper the rightness of motion transfer in the mechanism if the design parameters are well selected.