Novel quarter elliptical combinations chainring - the design and verification

Abstract

Pedaling by right and left legs will pass through two dead zone and power zone during cycling. The power zone is an area where the downstroke power can be transferred effectively, while the dead zone is an area where the leg power cannot be delivered maximally. Therefore, building a noncircular chainring shape considering the power phase and dead zone on the chainring could be a strategy to improve pedaling performances. This paper introduces a method to connect four superellipse curves to be a chainring shape with flexibly adjustable vertical and horizontal axis lengths. Thus, the noncircular chainring design conceptualized can be constructed easier. Here, the introduced two novel chainring prototypes are designed using the proposed method to maximize the pedaling on the power zone by enlarging the chainring radii around that area and reducing the chainring radii around the dead zone to overcome the dead zone effect. Verification is performed by comparing the pedaling test results between the two novel prototypes, the circular chainring and the popular commercial elliptical chainring (Q-ring). The results show that pedaling with the two novel prototypes is more efficient than circular chainring. Moreover, it can generate a cycling speed faster than the other chainrings tested on the same number of teeth.