Front and Rear Swing Arm Design of an Electric Racing Motorcycle Mechanical Engineering

123 Pages·2016·4.5 MB·English

by  João Ramos

Front and Rear Swing Arm Design of an Electric Racing
Motorcycle
João Diogo da Cal Ramos
Thesis to obtain the Master of Science Degree in
Mechanical Engineering

Supervisor: Prof. Luís Alberto Gonçalves de Sousa

Examination Committee
Chairperson: Prof. João Orlando Marques Gameiro Folgado
Supervisor: Prof. Luís Alberto Gonçalves de Sousa
Member of the Committee: João Manuel Pereira Dias
November 2016
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Dedicado aos meus pais

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Acknowledgments

The author would like to express his most sincere gratitude to his supervisor, Prof. Luis Sousa.
This was not the shortest of rides, but his knowledge, patience and friendship were always
there when needed. It was an honour and a privileged to work with him.
To all TLMoto team members. It was a pleasure to learn and work so much with great future
engineers on this passionate topic.
To my family. My father and my mother. This is as much my success as it is yours.
To all my professors, family and friends, thank you.

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Resumo
A indústria motociclista lida atualmente com os novos desafios impostos pelo design de
veículos elétricos. As soluções mais vanguardistas são por vezes testadas primeiro no mundo
da competição. Este estudo pretende examinar o design inicial e consequente processo
iterativo de melhoramento dos braço oscilante traseiro e frontal, de acordo com as regras
impostas pela competição MotoStudent. Todas as partes desenhadas foram concebidas para
serem fabricadas na liga de alumínio 7075-T6 e maquinadas em CNC. O Método Clássico de
Cossalter é de medição da rigidez de braços oscilantes foi complementado com um novo
estudo de condições sob carga vertical extrema (3580 N no perpendiculares ao eixo da roda).
FEA foi usada no processo de simulação iterativo de diferentes modelos sob condições de carga
vertical, torsional e laterais. Os modelos finais do braço oscilante traseiro e frontal respeitam
o coeficiente de segurança 𝑛 = 1.82 e os intervalos de rigidez de Cossalter (𝐾 = 0.8-
𝑝𝑟𝑜𝑗 𝑙𝑎𝑡𝑒𝑟𝑎𝑙
1.6 kN/mm and 𝐾 = 1-2 kNm/°). O peso final atingido em ambos foi, 4,86 kg and 2,84
𝑡𝑜𝑟𝑠𝑖𝑜𝑛𝑎𝑙
kg, respetivamente. No entanto, a complexidade final de ambas as partes devido a pormenores
internos e numerosas soldaduras torna a maquinação por CNC inviável. Um novo Sistema de
direção frontal foi proposto para a consequente utilização do braço oscilante frontal.

Palavras-chave:
Design estrutural, mota, braço oscilante, veículos elétricos, FEA, CAD,
CNC
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Abstract
Motorcycle manufacturers worldwide grapple with the new design challenges posed by
electric motorcycles. The competition world is where the most cutting edge design
solutions are firstly tested. The present study examined the initial design and consequent
iterative process of improvement of both rear and frontal swing arms for an electric
motorcycle according to the rules of the MotoSudent competition. All parts were designed
to be fabricated in aluminium alloy 7075-T6 and CNC machining. The classic Cossalter
approach for stiffness measurement of swing arms was complemented with new studies in
extreme vertical loading (3580 N perpendicular to the wheel axle). FEA was used through
the iterative process of simulating different swing arm models under vertical, torsional and
lateral loads. Final models for rear and front swing arms comply with derived safety
coefficient factor of 𝑛 = 1.82 and Cossalter’s stiffens intervals (𝐾 = 0.8-1.6
𝑝𝑟𝑜𝑗 𝑙𝑎𝑡𝑒𝑟𝑎𝑙
kN/mm and 𝐾 = 1-2 kNm/°). Final weight of achieved for rear and front swing arm,
𝑡𝑜𝑟𝑠𝑖𝑜𝑛𝑎𝑙
4,86 kg and 2,84 kg, respectively. However, final complexity of parts proved to have to many
welds and internal details for CNC machining to be a viable option. As an outcome of the
new design proposals for the frontal swing arm, a new steering system was conceived.

Keywords:
Structural design, motorcycle, swing arm, electric vehicles, FEA, CAD, CNC
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