Help with CAD for an involute face/crown gear.

Technical Technical Discussion
#1

I’m trying to cad a crown gear for a project and I’ve tried searching for how to cad an involute crown gear but I haven’t been able to find anything. There is some info on cading a basic crown gear but for this project I want to use involute pinions. I know that there is software out there that will do this but I can’t afford it and don’t have access to an educational copy of it. Does anyone know how to cad this. I can cad in Inventor 2018 or Solidworks 2017. (or fusion 360 but the other software would be preferred)

Here is a image link for what I’m trying to achieve

#2

I often search SDP to see if they already have the gear(s) that I am looking for. They have one of the largest selections and have CAD downloads for everything. Even if everything about their file isn’t exactly how you want it, you can download from them for the tooth profile and then modify the file from there.

Otherwise you really need a gear profile program. I believe there are a couple basic free ones out there, but the rest cost money. I haven’t ever desperately needed it, so I’ve never looked into it much. Designing tooth profiles from scratch is a pretty big PITA and I’ve generally gone by the philosophy that nothing in FRC should require that much custom design work.

#3

I tried searching involute, but im not sure what it means. Can you clarify which part of it is the involute? :confused: :ahh:

#4

I posted this spreadsheet a few years ago. It only does spur gears, though.

#5

May I ask what you would be using this for?

If you just need to transfer power at a right angle, other options might be easier to design, such as standard bevel gears, worm gears, or skew helical gears.

Just my $0.02, not knowing the needs of the potential application

#6

it seems like that link goes to all white papers.

#7

Here is the corrected link.

#8

I’ve tried SDP/SI, as far as I could tell they don’t have crown gears stock. This is for a college/for fun project. So the reason I’m looking into crown gears is to minimize the number of custom parts I need. With bevels you have to have two mating bevels and if you need to change the ratio you need to redesign both parts whereas with crown gears I can just adjust the pinion and the mounting distance. Since this is for now a 3D printed part It is a lot easier to change the dimension of one part and adjust the pinion than it is for me to remake both bevels.

I could probably try to find a gear profile program just that is out of my budget for quite a while and this is a project I’m currently interested in and working on.

Involute gears are the most commonly used gear types, However the trick is for crown gears the crown gear has a different profile than a trapezoidal tooth, which is what most of the cad tutorials I have found use.

And the other reason I’m looking into crown gears is I have constraints in my x and y axis but my z axis is more free for adjustments. And since i want to test multiple ratios making one crown gear is easier than a bunch of bevel gear pairs.

#9

Pwnage has used MITCalc to assist in designing custom gears for FRC.
There are internal ring gear generators, spur and pinion generators and potentially bevel gear generators, though we have not used those.
The software is free to evaluate for 30 days.

Try KHKgears.net for various bevel gears, many different types. They provide 3d models of their gears to help you design them into your mechanisms.

Pwnage has been developing swerve drives for a few years now and we have created an “assembly” of FRC sized bevel gears. The following link can direct you to a folder of bevel gears, mostly KHKgear brand with the Vex bevel gears added for size comparison.

https://grabcad.com/library/variety-of-khk-bevel-and-hypoid-gear-cad-1

#10