Designing a new type of drive unit for the analysis of small plastic gears

Abstract

When testing small plastic gears, the accuracy is always a problem. These gears are typically designed to perform their function with certainty, while other operating factors, such as noise, efficiency, and the similar factors play a marginal role in design or are not even considered (VDI 2731, 2009). However, when designing such gears, the designer is forced to face the limitations of known and recognized standards, guidelines, and methods, as well as the special characteristics of the installation environment. The problems arising from these can be explored mainly through experiments. Experiments with gears can be costly in this case because they often require at least two orders of magnitude more accurate measuring instruments than we have been accustomed to with normal-sized gears, and obviously appropriate equipment is required. In many cases, the use of drive units described in this article is a good solution to the problem of costly equipment. These drive units can contain gears of a given wheelbase, and their output and input shafts have the same external dimensions. This simplifies the problems of the equipment and makes the effects of the errors well comparable. This article describes the purposes and how we have used this type of drive units at the Institute of Machine and Product Design so far, what limitations they have, and what solutions can be used to develop these drive units to be able to perform more accurate tests.