GEARBOX DESIGNIDEASMEE30003

Mim Eguiazarian - David Orlowski - Yasith Dhamsara - Myles O’Donnell

Our TaskDesigning a gearbox to complete given task:

• Pulling a mass of minimum 10kg up a sloped ramp of ~46 degrees

• Must pull the mass for a minimum length of 50cm

• Has to pull the mass up the slope in the quickest amount of time

Is to perform the task utilising only the Motor provided

Theory Relating To The Task• Torque - Lifting potential

• Gear ratios - Transfer of torque

• Shafts

• Bearings

• Lubrication

Analysing the Performance FormulaPerformance is calculated according to the formula:

P = m*g*h m*g*h t*V*I t*D^3

Important factors to minimise - D (longest Axial Distance) t (time taken to travel 50cm)

Must base design around a compromise between the two to obtain greatest performance.

Initial Ideas For DesignKeep it simple

Simple constant mesh arrangement of spur gears with trains - Worried about torque

Planetary gears/Epicyclic gearbox - Compact - May be too difficult

Keep a small footprint for the gearbox

Offset gearbox arrangement

Gearbox Concepts

Key <--· Black - Motor· Grey - Outer casing· Green - Shaft and Shaft Supports · Red, Blue and Yellow - Gears

o Red - Stage 1 Gears with Ratio of 4:1o Blue - Stage 2 Gears with Ratio of 3.5:1o Yellow - Stage 3 Gears with Ratio of 3:1

Overall Ratio: 4*3.5*3 = 42:1

Mooted idea

Initial CalculationsCalculating the Minimum Theoretical torque of the gear shaft needed to lift the weight up the ramp

Initial CalculationsEquations used to calculate the changes in the torque

and angular speeds with the relative gear ratios

ReferencesArticles of Interest

Gear train optimization based on minimum volume/weight design

Golabi, Sa'Id ; Fesharaki, Javad Jafari ; Yazdipoor, MaryamMechanism and Machine Theory, March 2014, Vol.73, pp.197-217[Peer Reviewed Journal]

A practical approach to the optimization of gear trains with spur gears

Marjanovic, Nenad ; Isailovic, Biserka ; Marjanovic, Vesna ; Milojevic, Zoran ; Blagojevic, Mirko ; Bojic, MiloradMechanism and Machine Theory, July, 2012, Vol.53, p.1(16)[Peer Reviewed Journal]

Books of Interest

Fundamentals of Machine Component DesignJuvinall, RC & Marshek, KM, Fundamentals of Machine Component Design, 5th edn, Wiley, 2013

Design Basic of Industrial GearboxesAndrzej Maciejczyk ; Zbigniew Zdziennicki

Websites of Interest

www.engineeringtoolbox.com