This document discusses the design of a gearbox for a project to move a 10kg weight up a 1m long, 0.725m high ramp. It considers various gearbox types including spur gears, bevel gears, worm gears, cycloid gears, helical gears, hypoid gears, and planetary gearboxes. It provides details on the performance criteria for the gearbox as well as research on materials, gear types, and practical gearbox designs. The proposed design uses two compact planetary gear systems connected to a final gear and spool to wind up wire and move the weight up the ramp.

1. Creative Journey
Machine Design MEE30003
Nathan Scanlon, Jesse Cowley, Nor Azzafri and Akmal Husni
1

2. Design Brief
Gearbox Project:
Restraints
o Materials: 1xA4 sheet of Acrylic, glue and string
o Method: Laser cut
o Motor:
o 6V
o 9,000 RPM
o 2.3mm driveshaft
o M2.6 threaded mounting
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3. Ramp Details
• 1m long
• 0.725m high table
• 10kg weight
• Weight must move minimum 0.5m up
ramp
• Gearbox must be secured to mounting
plate at top of ramp provided
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4. Performance Criteria
𝑝 =
𝑚𝑔ℎ 2
𝑡2 𝑉𝐼𝐷3
High Importance (in order):
• Small axial length of gearbox (D)
• Low time (t)
• Large height reached (h) (for
completion)
Other considerations:
• Factor of safety
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5. Project Mind Map 5

6. Acrylic
Dimensional Stability
• Expand and contract with changes
in temperature and humidity.
• Develop permanent deformation
under continuous load.
• Good tensile and flexural strength
properties.
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7. Gearbox Research
Types of gearboxes:
o Bevel gearbox
o Helical gearbox
o Spur gearbox
o Worm gearbox
o Planetary gearbox
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8. Spur Gears
o Commonly used in series
for large gear reductions
o Mounted in parallel on
separate shafts
o Can be used in planetary
arrangements
o Easy to form with laser
cutter
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9. Spur Gears
Important equations:
•
𝜔 𝑝
𝜔 𝑔
= −
ⅆ 𝑔
ⅆ𝑝
• 𝑐 = Τⅆ 𝑝 + ⅆ 𝑔 2 = 𝑟𝑟 + 𝑟𝑔
• 𝑝 =
𝜋ⅆ
𝑁
9

10. Bevel Gears
(Straight)
• Used to change direction of the
shafts (90 degrees)
• Ratio range is normally 3:2 to 5:1
• Efficiency similar to spur gears (93-
97%)
• Can cause clashes and broken
teeth on start up like all straight
teeth gears
10

11. Bevel Gears (Spiral)
• More efficient than straight with 95-99%
efficiency
• Ratio is normally 3:2 and 4:1 (less than
straight)
• Less noise and vibration than straight
bevel
11

12. Worm Gears
 Large gear reductions
 Worm can easily turn the gear, but the
gear cannot turn the worm
 Low Efficiency,
 Lots of energy loss through the worm
and gear
12

13. Cycloid Gears
• Taking up a lot less space
• Comparable efficiency
• The bearing and the sun
gear are an unbalanced
mass causing vibration.
13

14. Helical Gears
o The teeth is cut with angle
o Operate more smoothly
and quietly
o Used for spiral bevel,
hypoid gear, worm gear
etc.
o Hard to be manufactured
with laser cutter
14

15. Hypoid Gears
o Spiral bevel gear change
shape from conical to
hyperboloid shape
o The axes of shaft does not
intersect
o High gear ratio range
o Hard to form with laser
cutter
15

16. Parallel
Compounded Gears
• Give a ratio besides 1:1
• Used to reduce RPM’s or Torque
• Single gear to gear max ratio about 5:1
• Advantage: often easier to
manufacture
• Easier to worm with
• Not as Compact as other methods
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17. Planetary
Gearboxes
o High gear ratio for a
compact size
o Several gears share the
load rather than one
o Difficult to implement
o Must be very accurate for
laser cutting
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18. Practical Research
• Winch Gear Box: Planetary System
• Only 1 set
• Ratio 250:1 approx.
• Spur Gears
• Material: Steel
18

19. Design Ideas
o Input from motor
connected into…
o Two Compact Planetary
systems
o Output onto small pinion
o Pinion to final gear (spool)
o Wire winds up onto spool
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20. Design Ideas
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21. Design Ideas
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22. References
• "6V 9,000 RPM DC Electric Motor". Jaycar Electronics. N.p., 2017. Web. 16 Mar. 2017.
• "Helical Planetary Gearboxes: Understanding The Tradeoffs". Design News. N.p., 2017. Web. 16 Mar. 2017.
• "How Gears Work". HowStuffWorks. N.p., 2017. Web. 16 Mar. 2017.
• "Spur Gears | KHK Gears". KHK Gears. N.p., 2017. Web. 16 Mar. 2017.
• "Advantages And Disadvantages Of Planetary Gearmotors". Bodine Electric Gearmotor Blog. N.p., 2017. Web. 19 Mar. 2017.
• "Bevel Gear". En.wikipedia.org. N.p., 2017. Web. 16 Mar. 2017.
• "Comparison Of Gear Efficiencies - Spur, Helical, Bevel, Worm, Hypoid, Cycloid". Meadinfo.org. N.p., 2017. Web. 16 Mar. 2017.
• Gonzalez, Carlos. "What’S The Difference Between Spur, Helical, Bevel, And Worm Gears?". Machinedesign.com. N.p., 2017. Web. 16 Mar. 2017.
• "How Gears Work". HowStuffWorks. N.p., 2017. Web. 16 Mar. 2017.
• Juvinall, Robert C, and Kurt M Marshek. Machine Component Design. 1st ed. New Delhi: Wiley, 2013. Print.
• "Planetary Gear Ratios Calculator". Torcbrain.de. N.p., 2017. Web. 19 Mar. 2017.
• "Planetary Gear Reducer: Rotating Around The Sun – Groschopp". Groschopp.com. N.p., 2017. Web. 19 Mar. 2017.
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