A dynamic model to predict the number of pins to transmit load in a cycloidal reducer with assembling clearance

In the ideal design of a cycloidal reducer, the tooth profile of cycloidal gear can make contact with all pin teeth on the pinwheel, wherein half of the pin teeth participate in load transmission. Meanwhile, the output holes on a cycloidal gear can maintain contact with all pins on the output disc and half of the output pins deliver load. However, under the influence of the assembling clearance caused by tooth modification, manufacturing tolerance, or machining error, the numbers of pins that participate in force transmission on both pinwheel and output disc fails to reach half of the total available. The objective of this research is to present a dynamic model to precisely predict the number of pins used to transmit load in a cycloidal reducer with assembling clearance. The methods for contact detection among the transmitting components are given in detail. In modeling of the contacts, both normal contact, and tangential friction, forces are considered. Finally, a typical cycloidal reducer with a single cycloidal gear is modeled and used as an example to analyze the variation of the number of pins that take part in load-bearing work under the influences of assembling clearance and external torque.