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Design of Spur Gears for a Gearbox

  1. Aug 15, 2016 #1
    I need to design and find suitable specifications for spur gears for a two stage reduction gearbox. The gearbox has to transmit 5kW at an output rotational speed of approximately 125 rev/min. The gearbox will be driven by a separate mains 4 pole synchronous electric motor . The required service intervals of the gearbox must be around 10,000 hours of continuous operation. Gearbox must be self contained and should have means of bolting to a baseplate. External lubrication is required.

    Any help with the spur gears specification and sizing requirements?
  2. jcsd
  3. Aug 15, 2016 #2


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    Do you have any education or experience in the design/sizing of a gear? It seems to me your best bet is to find an off-the-shelf gearbox or gear combination which is specced for your particular requirements.

    Given your power and speed requirement, you can also calculate the torque the gear has to be designed for. See here:

  4. Aug 15, 2016 #3
    Thanks for your reply , but do you have any idea where I can start with spur gear design?
  5. Aug 15, 2016 #4


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    I recommend starting with a text book which covers the design considerations of such a component.

    Like this one: https://amzn.com/9814595284 [Broken]
    Last edited by a moderator: May 8, 2017
  6. Oct 23, 2016 #5
    Reffer Gear Handbook by Darle W Dudely.
  7. Oct 23, 2016 #6
    Why are you even designing this at all? Clearly having no experience, it seems like a perfect thing to outsource to me.
    It's a nice contained black box, define your interface, what you want it to do. Boom.
  8. Oct 23, 2016 #7


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    Most of the gear and gear box manufacturers provide similar information . Use it to learn about gear technology and then you can negotiate with your chosen manufacturer in a constructive way .

    To actually design a gear box from scratch would be difficult for someone with no technical knowledge .
  9. Nov 6, 2016 #8
    Calculation procedure for spur gear specifications for the gearbox can be split into the following broad categories -
    1. Gear arrangements
    2. Gear tooth proportions
    3. Centre distance
    4. Calculation of gear tooth profiles
    5. Determination of gear tolerance
    6. Determination of gear materials
    7. Gear drawing
    8. Gear reactions and mountings
    9. Load ratings of gears
    10. Lubrication of gears
    11. Gear manufacturing

    all given in ........
  10. Nov 8, 2016 #9
    Mechanical engineers working in transmission field would often have to decide upon kind of gears they have to use. Although this task has become a matter of selection of gear based on standards, it is also important to know what goes behind this. In this video tutorial you will learn how to design a pair of spur gears for mechanical strength, surface resistance and fluctuating load.
  11. Nov 8, 2016 #10
    which video ?
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