The velocity ratio (VR) in gears and wheels systems is defined as the diameter or number of teeth on the input wheel divided by that of the output wheel. This definition differs from the calculation of VR for levers, where angle change is constant. The mechanical advantage will always be lower than the velocity ratio due to factors like dead weight and friction. It is crucial to independently verify calculations rather than solely relying on potentially unclear textbook explanations.
PREREQUISITESMechanical engineers, physics students, and anyone involved in the design or analysis of gear systems will benefit from this discussion.
It's exactly the same but you need to read the small print about what VR really means. The velocity ratio is the diameter (or number of teeth) of the input wheel divided by the diameter of the output wheel. That follows the definition. You cannot compare it with the way VR is calculated for levers because, with rigid levers it's the angle change that stays the same but, for gears in mesh, it's the tangential distance.Crissy said:
I can't read what the book actually says - it's too blurry with no contrast. But I think, if you read the book carefully (as I cannot) then you should find the distance moved by the Input and output teeth is the same but the input torque is Input Forcein times its radius and the output torque is Forceout times its radius. If you are still confused then, rather than trying to make sense of the book, work it out independently. Unless the book is actually wrong (never impossible to find a typo) your final result will agree with it.Crissy said:
