Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Epicyclic gear:modules for the sun,planet and ring gear

  1. Oct 13, 2013 #1
    Is the module(M) of the sun,planet and ring gear in a 'planetary gear set' equal to each other always? Is it possible for M to be different for each of the gears in the set?[-Applications of this?]

    $$PCD_{Ring}=PCD_{Sun}+2*PCD_{Planet}\Rightarrow N_{Ring}=N_{Sun}+2*N_{Planet}$$

    is valid only when the modules of all the 3 gear types are same.

    PCD- pitch circle diameter
    N- no. of teeth
  2. jcsd
  3. Oct 13, 2013 #2


    User Avatar
    Science Advisor

    All gears that mesh together must be of the same module or DP.
    If that was not so the teeth would not be in rolling contact.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook