I am using Autodesk Inventor 2011 to model a manipulator to practice CAD for this season.
I am wondering where I can find models of various diameter gears? I already have the 2011 KOP and I didn’t see any gear models in there. I also checked McMaster but I couldn’t find models for anything.
DO you guys know of any other websites where I can find many different sizes of gears?
There are two ways you can go about this. First, try Inventor’s built in Design Accelerator. This is by far your best bet. Not only will it generate the gears for you, but it will give you the optimized ratios and force calculations.
If for some reason you find the Design Accelerator unsuited for your application, go to SDP-SI.. Their CAD Library is extremely complete and I am almost certain you can find what you need there.
You might find it a useful exercise to grab a major gear vendor’s catalogue (Boston, Martin, SDP/SI, etc.) and pick one series of gears you’re likely to use during the next season—and model it for yourself. That way you have a model that you know works well with your CAD software, and which doesn’t contain any potentially undesirable simplifications (as many gears available online do).
First, start with a basic design with as much detail as you need. (Years ago, it made a lot of sense to avoid modelling individual gear teeth, when the pitch circle was more or less sufficient; nowadays it isn’t that much of a problem, because computers are much faster. Your choice.) This will give you a good feeling for the features of common gears, and which of those features are well-defined in catalogues (and which, like chamfers, aren’t). It will also give you an opportunity to learn about CAD support for things like material properties.
Then build yourself a parametric model of that entire gear series. In Inventor, Pro/ENGINEER (Creo) or SolidWorks, you can build a family table of associated parts, each representing variations on the same basic design. When you need a part, instead of downloading a new one each time, you just pick the element directly from your table—and can switch between table members without resolving part dependencies.
For example, 32 (diametral) pitch, 20° pressure angle gears* are commonly used in the first stage of a custom gearbox using RS-550 motors. Boston’s YP series and SDP/SI’s S1084Z-032 series are good candidates for this sort of practice.
*0.8 module, 20° pressure angle gears are very similar to 32 pitch gears (not identical: 31.75 pitch), and in FRC applications can generally be run together with minimal ill effects. (Not ideal, but far from the worst gear mismatch that teams have gotten away with.)
I second this. Also, if you download the gears in a native file format (which for me was Inventor) the original author made it incredibly easy to change the “number of teeth” user parameter and generate a new gear on the fly. For instance, I was able to download their 45 tooth DOG gear, change N Teeth to 60, and have a 60T DOG gear with minimal effort.
After checking out team 1323’s website I decided to go with the Design Accelerator gear generator. One more question:
I found the models for the different tubes from Logomotion on 3dcontentcentral.com but I couldn’t find the .ipt version. Does anyone know where else I could find the CAD models of the circle, square, and triangle from last year?
You could just download the models from 3dcontent central in a step or iges format and import it into inventor with no issue. If you are looking for a model that was created in inventor that might be something you have to make yourself.
Also another option for the gear issue is to use what called an i-model Ed Sparks created a very nice on that can be found on http://firstcadlibrary.com/ under gears and its at the bottom of that page.