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MEE30003 - Gearbox Project Will Huson - 7694210 Brent Farnsworth - 4922581 Jarrod Kline - 7694172

Gearbox presentation

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Page 1: Gearbox presentation

MEE30003 - Gearbox Project

Will Huson - 7694210Brent Farnsworth - 4922581Jarrod Kline - 7694172

Page 2: Gearbox presentation

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

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Motor Specifications

Jaycar YM2712 Max power:

Power Output = 6.44 WSpeed = 7845 RPMTorque = 80 g.cmCurrent = 2.6 A

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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

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Acrylic Uses• Automotive/ transport• Glass substitutes• Furniture• Lighting• Architecture

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Gear Arrangements

Possibilities Advantages and Disadvantages

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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

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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

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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

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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

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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

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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

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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

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System Losses

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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

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Projected Performance

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Gear Arrangement

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Next Steps

Model CAD Formation CNC First Cut

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Questions