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Torque on a coupled object

  1. Oct 25, 2015 #1
    Hello All,
    I have a quick question about torque and how it transfers to a coupled object. I am coupling a DC motor onto a worm gear and I need to calculate the tangential and axial forces on the worm. The Tangential Force equation is as follows:

    Fwt = (2*M1)/d1 where Fwt is the tangential force of the worm, M1 is defined as the worm torque and d1 is the referenced diameter of the worm.

    My question stems from the M1 variable and is it just simply the output torque from the motor it is coupled to or would I need to modify the torque value before I input it into the tangential force equation? The only reason I am questioning things is due to torque being dependent upon the length of the lever arm (shaft diameter in this case) and the worm gear shaft is larger than my motor shaft.

    I appreciate any help into my confusion.
  2. jcsd
  3. Oct 27, 2015 #2


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    I'm not familiar with the equation you mention (not my field) but the above is wrong.

    If the system loads up the motor so that the motor is generating X Nm of torque then that's the torque in the motor shaft regardless of the shaft diameter of the motor. If the worm is connected to the motor shaft then the worm torque is also X Nm.
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