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Gearbox presentation
- 1. MEE30003 - GearboxProject Will Huson - 7694210 Brent Farnsworth - 4922581 Jarrod Kline - 7694172
- 2. Design Brief Gearboxbuilt 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
- 3. Motor Specifications JaycarYM2712 Max power: Power Output = 6.44 W Speed = 7845 RPM Torque = 80 g.cm Current = 2.6 A
- 4. Acrylic Properties • Transparent,colourless • Easily shapeable • Scratch resistant Property Value Young’s Modulus 1.8-3.1 GPa Bending Strength 120-148 Mpa Fracture Strength 48-76 Mpa Friction Coefficient 0.54 Density 1170-1200 kg/m3
- 5. Acrylic Uses • Automotive/transport • Glass substitutes • Furniture • Lighting • Architecture
- 6. Gear Arrangements Possibilities Advantages and Disadvantages
- 7. Spur Pros Simple touse 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 power Cons More expensive than worm gears Limited tooth interaction between mating gears, which reduces the torque carrying capacity Produces noise at high speeds
- 8. Helical Pros Highlyefficient gear (94% - 98% efficiency) Has more teeth constantly interacting producing high torque Smooth and quiet operation Highly durable Ideal for high load applications Cons 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
- 9. Bevel Pros Can interactwith 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
- 10. 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
- 11. Worm Pros Inexpensive Quiet Smooth when running in only one direction They take up less space Cons Not the highest efficiency (50% - 90%) Experience sliding friction, creates heat and increases tooth wear If motor reverses, teeth will wear
- 12. Planetary Pros Creates highgear 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
- 13. Selection - SpurGear • 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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- 15. Projected Performance Radius ofdraw 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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- 18. Next Steps Model CAD Formation CNC First Cut
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