An optimum non-circular chainwheel design for a bicycle drive system

Han, Ray P. S.; Alexander, Karen

doi:10.1016/0016-0032(93)90072-3

Cited by 4 publications

(4 citation statements)

References 8 publications

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“…This is because the Q-ring has a larger major axis than the circular chainring 34T in the pedaling power phase area, similar to the circular chainring 35 teeth radius. This significant result is in line with the previous studies (Han and Alexander, 1993;, where Q-ring can increase the speed output in cycling performance.…”

Section: Speed Level Cadence [Rpm]supporting

confidence: 93%

“…However, the studies focused on developing the noncircular chainring geometry to improve cycling performance are still limited. Han and Alexander (1993) developed an optimum noncircular chainring design using an ellipse curve to adapt the pedaling torque graph. The proposed design is suitable for low speed based on the simulation results.…”

Section: Introductionmentioning

confidence: 99%

“…Theoretically, the variability in speed produced by the non-circular chainring shape is advantageous for the cycling mechanism (Han and Alexander, 1993). Pedaling has certain positions where the leg power cannot be delivered maximally (at the top and bottom dead zone) (Duc et al, 2020;Turpin and Watier, 2020;Vidal et al, 2020), and some other positions where the leg power will be delivered effectively (at the power zone) (Dorel et al, 2009;Turpin and Watier, 2020).…”

Section: Introductionmentioning

confidence: 99%

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Novel quarter elliptical combinations chainring - the design and verification

Lesmawanto

Chang

2023

JAMDSM

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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.

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Section: Speed Level Cadence [Rpm]supporting

confidence: 93%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Novel quarter elliptical combinations chainring - the design and verification

Lesmawanto

Chang

2023

JAMDSM

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“…Some studies have proposed different shapes of sprockets in order to optimize cycling performances. Han and Alexander (1993) proposed an ellipse shape as an optimum sprocket design at low speed. Rankin and Neptune (2008) introduced an ellipse sprocket from the theoretical analysis to increase the pedaling on the power phase.…”

Section: Introductionmentioning

confidence: 99%

Computer-aided design of bi-ellipse bicycle sprocket

Lesmawanto

Hsu

Chang

2022

JAMDSM

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In cycling, pedaling is a combination of two pedal strokes by the left and right legs with different power. The pedaling power is transmitted from the human leg to the bike through the sprocket mechanism. However, research on sprocket design that considers the combination of two pedal strokes is limited. This paper proposes a CAD method to design a bi-ellipse sprocket that combines half different ellipses. The ellipses combination is used to accommodate the different torque between two pedals. Here, we built a sprocket prototype by adjusting the two vertical axes ratio on the bi-ellipse sprocket to be equal to the maximum torque ratio on the left and right crank. Then, we performed a pedaling comparison test between the circular sprocket and bi-ellipse sprocket prototype at the same rear-wheel rotational speed using a mountain bicycle mounted on an indoor bike trainer. In the test, the bi-ellipse prototype was also set up in eight different positions to the crank. Crank meter systems were installed on the bike to obtain the pedaling torque data and the pedaling power data on the left and right crank every 0.005 seconds. The result showed that the comparison parameter related to crank torque and power had smaller values on the bi-ellipse prototype than pedaling on the circular sprocket. Moreover, the asymmetry index of maximum torque in a specific position on the crank was lower than the circular sprocket. It can be concluded that using the bi-ellipse sprocket prototype makes pedaling more efficient, lighter, and safer to use. The proposed method can also be used as a guidance procedure to make countless bi-ellipse sprocket models.

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