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Creative journey
- 1. Triple M Team Creativejourney A discussion of Spur and Planetary gear sets
- 2. Understanding the problem:Performance Equation Where; m= Mass to be Lifted (10kg) g= Acceleration due to gravity h= Height the weight is lifted (0.5m) t= Time to lift weight by distance h V=Motor Voltage I=Motor Current D= Maximum Axial length of the gearbox
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- 4. High torque Smallform factor Compatible with orthogonal cut Spur x x Helical x Bevel x Worm x x Rack and pinion x x Planetary x x x Possible solutions
- 5. Planetary gears vsCompound gear discussion Planetary Compound (Spur) ● High Torque ● A Compact alternative to standard Compound gearboxes. Which can produce the same reduction ratio at a significantly reduced size. ● The Load is evenly distributed amongst the planetary gears. Therefore, additional planetary gears may be added in the case of high loads. ● High Efficiency ● Complex Design ● High Torque ● Significantly larger in size for an equal reduction ratio, therefore more material usage. ● High load at the point of contact, therefore is prone to tooth wear. ● Loud at high RPM, due to low Contact Ratio. ● Simple Design, easier maintenance.
- 6. Required Gear Ratio: ●Assuming a Coefficient of friction of 0.25 was used, a gear ratio of 34:1 is required in order the lift 10kg a minimum of 0.5m.
- 7. Our solution theplanetary gear set Why we went with the planetary; The calculated Data clearly states that at an equal ratio, the planetary gear required a significantly reduced Pitch Diameter. Therefore, resulting in a more compact design.
- 8. Initial Designs In aplanetary gear motor, the input shaft drives the central (sun) gear, which then turns the surrounding (planet) gears. This arrangement allows each of the planet gears to deliver torque in perfect synchronization with the others, which leads to greater output capacity and takes the pressure off of each individual gear. Planetary gearSpur gear
- 9. What’s wrong withour solution: Complexity: The relative complexity of the planetary gear set is a problem with our solution. A spur gear set does not need the tolerances to be so tight. Torque is limited in spur motor gears since each gear bears the whole load. There are more components in a planetary gear set, therefore a higher risk of problems in manufacturing errors and human error
- 10. What is rightfor our solution: The planetary gear set has a high power to size ratio. It therefore should reduce the amount of material needed for manufacture A planetary gear motor shares the torsional load over several planet gears, so it works well when a higher torque is required. So there is less worry about wear and stress, which makes it easier to attain large amounts of power transfer without harming the gears.
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