The throttle motor gearbox has been designed to be simple to integrate into robot designs, the gearbox shaft smoothly slides through the 1/2 inch hex hole in the gear assembly. This enables teams to use any length gearbox shaft they like, without having to purchase expensive couplers. The gearbox will be sent out with bushings, and it will be simple for teams to replace these with 1/2 hex flanged bearings if they desire.
Images of the prototype throttle motor gearbox design:
http://imgur.com/a/uJlaR