There's a lot of confusion and mis-information here so let's simplify
The only time OSX/Apple touches windows drivers is during the initial install, boot camp assistant, windows support software, etc - complicating matters is Apple did relase an updated boot camp package a few days ago, but this is now also downloaded thru boot camp assistant for clean installs or via the web if you need to manually update an older package
After windows is installed, it runs just like windows on a PC namely all updates, drivers, etc come via windows update. Contrary to aidenshaw you can in fact setup windows update to automatically update your machine.
Drivers are not updated via windows update. They are updated via the Apple Update Tool