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• # Kinematic diagram of a gear mechanism

Discussion in 'Calculations' started by Pawllentiew, Mar 20, 2021.

1. ### PawllentiewNew Member

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Mar 2021
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Can anyone help me with a kinematic analysis for the mechanism attached below? I need the outline of the mechanism, its notes and the necessary formulas to find out the transmission ratio and the rest of the values. I'm a beginner and I can't do it at all. I would greatly appreciate a helping hand

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3. ### s.weinbergWell-Known MemberEngineeringClicks Expert

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You essentially have 3 stages:

1. Belt to pink pulley
2: pink gear to green gear
3: Planetary stage

I'm going to assume your motor is stationary, and so is the purple ring gear.
Have to assume there's a planetary carrier, not shown, that is your output.

Pulley reduction will be the ratio of the diameters, moving in the same direction.

2nd stage reduction will be the ratio of the diameters, reversing direction

3rd stage is slightly tricky because of the stepped planets. Check out the beginning of this article for the method called superposition to derive the gear ratio:
https://www.engineeringclicks.com/planetary-gears/

The reduction, I believe, is (1+(RingDiameter*PlanetSmallDiameter)/(SunDiameter*PlanetLargeDiameter) to 1)

Output in the same direction as the sun.

Multiply your various stages by each other and keep track of direction for total reduction and direction (one reversal, so opposite to motor is direction).

I assume that's confusing, so let me know where you'd like clarification

4. ### ErichWell-Known Member

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Feb 2012
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Its really pretty, but all the shafts are floating in space. You need to tell us what is anchored and cannot move or rotate, then we can help analyze the system. OR we can make ASSumptions like Steve did and analyze one or two cases. I am not willing to put in work until the original poster puts his in

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