Meshing Gears

[Travis Covington]

Although I will agree that meshing gears is an effective way to create a shifting gearbox, if reliability and consistency are a larger factor, then I would have to put my vote in for a shifting dog style tranny.

The benefits of the dogs are seen in a lot of real world applications, such as motorcycle transmissions and the like. Most motorcycles still use a clutch, where as most FIRST robots using a dog style tranny do not. The difference there is negligible, as most teams learn to back off on the joystick when they shift gears, but for the most part it is an insignificant factor for such low-torque applications. In alot of cases, motorcycles can be shifted without having to use the clutch.

While meshing gears works, there is the inherent wearing of the 'rouded' edge you folks are talking about that essentially helps ensure the gear is meshing. After long term use, these gear edges will see significant wear. The argument then follows, 'we won’t be using it THAT much on a FIRST robot, and so does the wear really matter?' I would probably say no. So overall, I say build what you are comfortable building. I know a lot of top teams use meshing gears, while other equally good top teams use dogs. I have not heard of many stories on either side where these transmissions fail in short term seasonal use.

Good luck either way...

Here is some motivation for you all... (Stock motorcycle tranny)