Gearbox ProjectCreativity Journey

VERTICAL RACK & PINION LIFT

- High stability- Hard to adjust- More suitable for smaller distances- Greater number of gears- Supports needed to keep rack in line

PULLEY SYSTEM

- Reduces torque at rotating shaft

- Increases length of string to lift

- Friction

SINGLE VS DOUBLE STRING SUPPORT

Single

- Simple, compact- High stress concentration in shaft- Overlapping of string increases Torque

required

Double

- Less concentrated force in shaft- Overlapping issue- Requires more space

SCREW/WORM WINDING

- Enables constant Torque

- Difficult to manufacture

Planetary Gear System• Advantages• Compact and lightweight• Higher efficiency• Less stress between teeth• Less distortion

• Disadvantages• Demands a higher degree of precision• More complex• Potentially difficult to make minor adjustments or replace parts after initial

assembly

• Sun gear: InputPlanetary Carrier: OutputRing gear: Fixed• This puts the gearing system in reduction mode. Sun will rotate faster than the planetary

carrier• Maximum gear ratio is 10:1; this is unlikely to be enough for our application• A two stage design could easily provide an

adequate gear ratio • However, complexity in assembly increases

even more with two stages

Worm gearboxAdvantages• Simple way to achieve a high torque.(Gear ratio from 10:1 to 500:1)• Quiet and relatively smooth while running in only one direction.• Small size less spaced required.

Disadvantages• Experience sliding friction.• Create heat causes energy loses .• Tooth wear increased.• 65%-80% efficiency.

Load

motor

Improvement of worm gearbox• Gear may or may not drive worm. • If the lead angle is small, the gear's teeth may simply

lock against the worm's teeth.• The force component circumferential to the worm is

not sufficient to overcome friction.

Load

motor

Compound Spur Gear Train• Simple to design and

manufacture• More compact than a simple

gear train• High efficiency for each

stage • More stages equals smaller

gear sizing but at loss of efficiency

• High stress in teeth

1:21:2

1:21:2

2-Stage vs 3-Stage vs 4-Stage (1:64)

2 X 1:8 3 X 1:4 4 X 1:2.26

Final Design• Planetary seems to be the more effective solution• However, given limitations we are leaning towards a standard

compounded gear train

• Why?• Much simpler design; assembly is an important factor• There will be issues that will need fixing/adjusting after the first cut• Easier maintenance will allow us to address more issues quicker