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MEE30003 - Gearbox Project
Will Huson - 7694210Brent Farnsworth - 4922581Jarrod Kline - 7694172
Design Brief
Gearbox built to lift an 8 kg weight Must lift to a height between 0.5 and 1 metre Will be powered by a provided motor Will be secured to a specified mounting plate Can only be made from acrylic, glue and string
Motor Specifications
Jaycar YM2712 Max power:
Power Output = 6.44 WSpeed = 7845 RPMTorque = 80 g.cmCurrent = 2.6 A
Acrylic Properties• Transparent, colourless• Easily shapeable• Scratch resistant
Property ValueYoung’s Modulus 1.8-3.1 GPaBending Strength 120-148 MpaFracture Strength 48-76 MpaFriction Coefficient 0.54Density 1170-1200 kg/m3
Acrylic Uses• Automotive/ transport• Glass substitutes• Furniture• Lighting• Architecture
Gear Arrangements
Possibilities Advantages and Disadvantages
Spur Pros Simple to use and manufacture Efficient due to the fact that the
teeth roll instead of slide (94%-98%)
No friction Supplies a constant velocity ratio Can transmit a large amount of
powerCons More expensive than worm gears Limited tooth interaction between
mating gears, which reduces the torque carrying capacity
Produces noise at high speeds
Helical Pros Highly efficient gear (94% - 98%
efficiency) Has more teeth constantly
interacting producing high torque Smooth and quiet operation Highly durable Ideal for high load applicationsCons Not self locking Would require precision
manufacturing and assembly from the materials at hand
Subjected to thrust load if double helical or herringbone gears are used
BevelPros Can interact with other gears on an
angle, which can make the gear box more compact
Can be quiet and smooth if spiral teeth are used
Efficiency of 93% - 97%Cons Most be precisely mounted Limited gear ratio The shaft experiences large force Each gear can only operate with its
complimenting gear
Rack and Pinion
Pros Robust design Compact and cheap to manufacture Easiest way to convert rotational
motion to linear motion
Cons Very inefficient Only works with certain levels of
friction Subjected to wear
WormPros Inexpensive Quiet Smooth when running in only one
direction They take up less spaceCons Not the highest efficiency (50% -
90%) Experience sliding friction, creates
heat and increases tooth wear If motor reverses, teeth will wear
PlanetaryPros Creates high gear ratios out of
compact gearboxes Low backlash Higher efficiency than a worm gear
(80% - 95%)Cons Can be damaged from shock loads Lower efficiency than a spur or
helical gear Gear ratios lower than 30:1 are not
possible If a tooth shears then the whole
system fails
Selection - Spur Gear• Simple to use• Easy to manufacture• High efficiency• The noise factor will not
be an issue as performance is the main concern
• If some teeth shear, the gears will still work
• If assembled in the correct way, can take up less space
System Losses
Projected Performance
Radius of draw shaft (m)
T req'd (Nm)
4 Gear Raise time (sec) Config. 3G ESF
0.005 0.3924 19.71938874B3 1.49
Projected Performance
Gear Arrangement
Next Steps
Model CAD Formation CNC First Cut
Questions