Society of Robots - Robot Forum

Mechanics and Construction => Mechanics and Construction => Topic started by: bellsofchime on April 15, 2010, 02:51:17 PM

Title: Rack & Pinion gear
Post by: bellsofchime on April 15, 2010, 02:51:17 PM
As a part of our assignment we were asked to do the analysis of a rack and pinion gear used in a CNC milling machine.
I really get confused of how the forces would act on the pinion and how would I determine the equivalent inertia of the gear system.

Title: Re: Rack & Pinion gear
Post by: nottoooily on April 16, 2010, 03:50:56 AM
rotational inertia for a point mass is
I = r^2 m
You can treat the rack as a point mass at radius equal to the radius where the teeth contact.

Similarly, if you know the force on the rack, the torque on the pinion is
torque = F r
Title: Re: Rack & Pinion gear
Post by: bellsofchime on April 16, 2010, 04:58:46 AM
Again, I have to find the Viscous friction for the system. I have been given Z axis viscous friction, Motor viscous friction and Gear head viscous friction. Please do help me with this term GEARHEAD in a rack and Pinion. and what is gearhead ratio 'N'....how to find it??? ???
Title: Re: Rack & Pinion gear
Post by: bukowski on April 18, 2010, 01:20:33 AM
The gear head is another name for the gear box, I believe. N would be whatever the gear reduction is.