I am working with the ISO spur gears for a project, where different sized gears fit together. I would like to know if it is possible to calculate the number of teeth for a gear, when i know the outside diameter of the gears and the distance between their axes?
i need a 1.6 to 1 ratio and 4.5 RPM at the final drive.
but the only parameters you can change in the toolbox that changes the size of the gear is module and number of teeth? and i need the gears to be of a certain size to fit the construction.
The module and number of teeth also define the diameter. You need a whole number of teeth, of course, so the three parameters are dependent and you don't have free reign on choosing centre distances. Bear in mind that when calculating the ratio and centre distance you need to work with the PCD, not the outside diameter. The outside diameters overlap. Forgive me if that seems obvious, but sometimes the obvious things are easy to forget :-)
There is good basic information on Gear - Wikipedia, the free encyclopedia.
Edit: at least, you are limited if you want to use off-the-shelf gears with standard modules. If you are going to cut your own gears you can vary the module to some extent, but even then there are practical limits on the number of teeth.
Magnus, you don't have enough information to determine the answer to your question. There are many different solutions to your question. What gear ratio to you need? Do you want a 2 to 1 or a 5 to 1, what RPM do you want to at the final drive. So many things factor in for the gears.
Bill