Gearbox Mentoring
 

I know this is a very "Rookie" Question but I will ask it anyway. Would anyone be willing to guide me and teach me how to design and build a custom gearbox?

Re: Gearbox Mentoring
 

Check out 973's videos. They cover the CAD part very well.

http://www.greybots.com/videos.html

Re: Gearbox Mentoring
 

I don't think they cover gearbox ratios and etc.

Re: Gearbox Mentoring
 

Are you more on the "Where do I start" part of the spectrum, or "I have a specific question?"

First step I usually tell students is to download the JVN Design Calculator.

Re: Gearbox Mentoring
 

PM me if you'd like me to help. Were you thinking more of an article / guide or more chat-style help? Do you have a particular application in mind?

Re: Gearbox Mentoring
 

Gearbox design involves quite a few topics. More than should be condensed into one post. I can address your ratio question in this one. (I'm assuming you are starting at the very beginning by the way)

For the purposes of this post we will ignore the existence of the rest of the gearbox in the attached photo (the rest of it should be coming up in CD media soon).

Highlighted/blue gear would be called the output gear and the smaller gear to the right attached to the motor is the pinion. Pinion refers to the gear attached to the power source or the input. Generally the gear ratio is expressed as the number of teeth of the output over the number of teeth of the input, in this case 44/11 or 4/1 or 4:1.

basically every time the pinion spins 360deg it advances 11 teeth and the output advances 11 teeth. 11 teeth = 1/4 of the teeth on the output gear resulting in 1/4 a rotation of it for every whole rotation of the input.

This US Navy video from 2:08 to 4:37 is a great example:https://www.youtube.com/watch?v=s1i-...jLyVmGXSxTl-KQ Note he exspesses his ratio as input over output or the reverse of what I use above.

Re: Gearbox Mentoring
 

I wish I had seen that pocketing video yesterday...

Re: Gearbox Mentoring
 

I did a presentation for my team's newer members on this and used this to explain and show gear ratios. http://www.gearsket.ch/

I also sketched up roughly what a drivetrain ends up being inside of it.http://i.imgur.com/frgi7EU.jpg?1

Re: Gearbox Mentoring
 

Be sure to note that 99.9% of the time, the ratio between the inter and outer wheels is 1:1. You've got a reduction from your center wheel to your outer wheels in the second image.

Re: Gearbox Mentoring
 

Yep, I know its drawn that way because of the limitations of the website