Agile Development of Polymer Power Transmission Systems for e-Mobility—A Novel Methodology Based on an e-Bike Drive Case Study

Abstract

The market for electric bicycles has grown extremely and developed rapidly in recent years. To enter such a market with a new product, the development process has to be fast, and throughout the process, feedback from future potential customer(s) should be sought in order to achieve the best possible market acceptance. The article presents the design process of a pedelec e-bike central drive system. The authors were members of the development team and the designers of the mechanical transmission, and therefore had a good overview of the whole project. The development process and the set-up of production require a certain amount of time, during which design changes are inevitable due to changes in customer expectations and demands. The development team should respond to these changes and take them into account during development. Only the ability to react to changes and constant communication with the customer will ultimately lead to a product that can be commercially successful. Based on a critical review of the successfully completed project, general guidelines were established for the development of mechatronic products that consider the principles of Agile methodology. Particular attention was paid to the development of polymer gears, as these were the most demanding components in the system. The presented guidelines were based on an overview of the e-bike R&D process presented, but they can be generalized and used in the development process of any technical physical product. Agile methods were developed in the field of software development and therefore cannot be directly transferred to the field of physical product development. The article highlights and discusses individual special features that distinguish agile development of physical products from software development.

Influence of Open Differential Design on the Mass Reduction Function

“…Therefore, certain research papers deal with the selection of materials for making gears, analyzing the behavior of the differential at different rotation speeds, different gear mesh frequencies and different natural frequencies [11]. Selection of materials, such as composite materials [12,13], or gearboxes with gears made from polymer materials [14], has an impact on the mass reduction of the transmission, corrosion resistance, less abrasive wear and improved energy efficiency. By varying different print densities when producing gears from Acrylonitrile Butadiene Styrene (ABS), it is possible to obtain gears of lower mass with lower print densities (60% ABS density), while the stresses in the gears meet the permitted stresses [15].…”