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Student Question

Secondary III • 1yr.


I have just learned about transmission mechanisms and I am not sure I understand the difference between motor, driven, and intermediate transmission mechanisms.

Also, I do not understand how the direction of a rotation can change or not, and how some systems are reversible and others not.

Can you give me some examples? Thank you :)


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Explanations (1)

  • Explanation from Alloprof

    Explanation from Alloprof

    This Explanation was submitted by a member of the Alloprof team.

    Team Alloprof • 1yr.

    Hello !

    Thank you for your question 😉

    A motor organ is an object which transmits its movement to another object, the driven organ. Both organs can be in direct contact, or there can be another object which transmits the movement of the motor organ to the driven organ. In the latter case, this third, middle organ is called the intermediate organ.

    A pulley and belt system are a good example. The first moving pulley constitutes the motor organ. It transmits its rotational movement to the belt, the intermediate member, which performs a translational movement, which generates the rotation of a second pulley, the driven member.

    A transmission system can rotate in the same direction or change direction. The rotational movement of a pulley system with direct belts always remains in the same direction. However, in a gear system, the rotation of a first toothed wheel generates a rotation in the opposite direction in the second.

    Finally, some systems are reversible. The driven organ can become a motor organ, and the motor organ a driven organ. This is the case with gear systems, in which each toothed wheel can generate movement in the other organs with which it is in contact.

    However, some mechanisms, like worm wheel gears, can only unroll in one direction. In this mechanism, only the screw can serve as a driving organ; if you try to move the screw from the wheel, the screw will jam.

    I hope this answers your questions! Don't hesitate to come back to us for more :)