Mechanical Advantage of Rack and Pinion

[adityagoti]

Hi All,

Can anyone tell me how to calculate the Mechanical advantage of the rack and pinion system. Thank You.

 

[kjoiner]

Hello,

When talking about the desired torque, is it the input or the output? In other words, are you applying a linear force to the rack and wanting an output torque at the pinion, or are you applying a torque to the pinion and wanting an output force at the rack?

You mention your limitation of a 4" diameter pinion. One thing you need to consider, is the pitch diameter of the pinion. The pitch diameter of the pinion will be less than the OD of the pinion.

Either way, if considering a "friction wheel" (where you could actually have no slippage - not real world) situation where you acutally have a 4" pinion surface moving a rack, you would actually have mechanical disadvantage since you would need to divide the input torque by the pinion radius. The only way you will have an advantage is if you applied the input force to the rack to get an output torque at the pinion.

This made me start thinking about arbor presses which depend on how hard you can pull on the handle which then made me realize why I did a favor and made a new handle for the one we have at work because someone put a cheater pipe on it and bent the original one.

Kyle