Creative JournalHUYNH LE, HAYDEN BURKE, JARRYD SYMONS, ASAHDULLAH FAHIM.

Introduction to the problem Our understanding the core problems face in this situation:

We are required to lift a mass (m) a vertical distance of (h) with the aid of an acrylic gearbox attached to a small motor in such a way that maximises p which is equal to;

Secondary issues (through brain storming) : Size restriction, material strength, stress on gear teeth, surface resistance, maximum allowable acrylic usage (A4), friction within the system.

From here we look at all possible gear types and configurations they could be arrange in to optimise p.

Planetary GearsAdvantages

Large reduction ratio High power density Compact size

Disadvantages

Complex in design Accurate gearing needed Low tolerance for error

Relation to the problem • Reduces axial length with compact size.• The planets share the load rather then one gear.• Reduces 9000Rpm motor to tolerable level for material

Planetary reduction setup -Sun gear as ‘driver’ and planets as ‘driven’

-Reduction ratio. -Fixed position outer ring gear.

Planetary Design

Disadvantages of The Design -Difficult to construct and assemble. -Cannot be mounted. -No room to account for motor and wall -Expensive to build.

Gearbox Design - Spur GearAdvantages:• High Efficiencies (up to 98%)• Simplistic; Easy to design &

manufacture --> Cheaper to make• Well Researched; Long History• Offers constant velocity ratio• No slip and creep as opposed to

belt/chain.

Disadvantage: • Cannot transfer power to non

parallel shafts• Spur gears are expensive compared

to belts.• Have limited transfer distance.• Noisy at high speeds• Gears experience a high amount of

stress.

Design Features – Housing• No partitioning walls

• Plates have holes for alignment

• Gearbox thickness is only 44mm, allows for introduction of additional gear sets

• Makes uses of rods to improve rigidity (rod is unlimited, rest is not)

• Whatever material left over we can use to further add to the housing. (Adding plates)

• Fixed Axial – Reduce induced friction on system

Design Features – Gear Mesh• Spacers are used to separate

gears instead of using partitioning walls. Thid decreases the area of rubbing between acrylic on acrylic. Coefficient of friction between acrylic and acrylic is 0.6-0.72

• More gearsets will decrease overall gearbox efficiency, with next evolution will try and decrease number of gearset from 6 to 5.

(http://www.matweb.com/search/DataSheet.aspx?MatGUID=3cb08da2a0054447a3790015b7214d07)

Design Features – Gear & Pinion• Gear has been optimized to

decrease its moment of inertia.

• Gear features two mechanism for joining, pinning which will offer shear resistance and super glue which will provide shear and axial load resistance from coming apart.

• Advantage of this is that first run can be done by simply pinning them and then reusing the 16T for next evolution.

• Pinning also serves as a method of alignment (doesn’t really matter with gears but does for .

Design Feature – Gear & Spool• I intend to cut a 1mm thick piece

and use it to put along pulley reduce friction more.

• Moment of inertia

Also note:• Designed to max efficiency setting,

therefore any unaccounted or unforeseen forces can be overcome by increasing the power from the supply. (Optimization tells us difference now)

• Friend has a hobby shop – Can test the efficiency of our gearbox.