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

Abstract

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.

Analysis of the cycloidal reducer output mechanism while taking into account machining deviations

“…The deflections of pins f j with the bushings mounted on them, and the deformations of the bushings d dj in contact with the holes of the planet wheel during operation of the cycloid transmission cause the backlash D j in the output mechanism, resulting from machining deviations of its elements and described by formula (1), to change. Its value can be determined using formula (19).…”

“…Backlash assumes the value greater than zero, because the sum of the remaining deviations, i. The backlash distribution D jw , which is presented in Figure 16, was determined from equation (19) and the data summarised in Table 1. In case 1, shown in Figure 16(a), the backlash D jw is so large that the last bushing comes into contact with the hole of the planet wheel.…”

“…The obtained results of computer simulations using Autodesk Inventor showed high convergence with theoretical analysis. In, 19 the author presented a dynamic model of the work of the transmission with gear backlash, which allowed the number of pairs of teeth in the cycloidal gear meshing and the number of bolts in the load-bearing output mechanism to be determined. The author showed that mounting backlash, resulting from the machining tolerances and machining errors of the transmission components, reduces the number of pairs of teeth and load bearing pins when compared to transmission without backlash.…”

Scaling laws for robotic transmissions

“…Of all parts of the cycloid drive, the output pins undergo the highest forces [31] and are therefore the most critical components. Consequently, their dimensioning will determine the scaling law.…”

Analytical investigation on load-sharing characteristics for multi-power face gear split flow system

“…24 proposed a generalized dynamic model for the bearing-cycloid-pinwheel transmission mechanisms (BCPTMs) that are used in robot joint rotate vector (RV) reducers to study the dynamic contact response and internal-load transmission characteristics of the BCPTM. Considering the normal contact and tangential friction forces, Xu 25 presented a dynamic model to precisely predict the number of pins used to transmit load in a cycloidal reducer with assembling clearance.…”