pic: Team 948 Shifting Transmission Version #2

[camtunkpa]

Looks good! Just remember to give yourself enough time to get the output shaft and gears heat treated.

[David Guzman]

Why do you say they have to heat treat them. I dont think there is a need, not for FIRST uses. But then again I am not an engineer. Do you mind explaining.

Thanks

David G.

[camtunkpa]

Originally Posted by David Guzman

Why do you say they have to heat treat them. I dont think there is a need, not for FIRST uses. But then again I am not an engineer. Do you mind explaining.

Thanks

David G.

We have always hardened both the output gears and shaft for two main reasons. Hardening both parts means no wear on parts and also reduces the chances of galling. The gears definately will need to be hardened if you plan on shifting under a full load condition. Testing before hardening the slots in the gears that the ball bearing pops into has shown a slight wear pattern. This wear pattern maybe due to just run in and not get any worse during the season however our team likes to have a nearly maintenance free transmission. I know teams who used a ball shifter that did not harden the output shaft or the gears and they had no problems, but we'd rather not have an extra part to keep track of on our machine. Build it simple and fool proof.

[David Guzman]

I see,

I designed a ball bearing shifter that is currently being tested but i did not take into a count hardening the gears. However I used 6 holes on the gears and 3 balls so there is not as much friction while shifting. But either way do you think you could describe the process for hardening the gears?

I would appreciate it.

Thanks,

David Guzman

[camtunkpa]

David,

We have a local company harden the gears and shaft for us. I don't know much about the process Maybe someone with more mechanical knowledge could explain the process of case hardening.

[lukevanoort]

Originally Posted by camtunkpa

David,

We have a local company harden the gears and shaft for us. I don't know much about the process Maybe someone with more mechanical knowledge could explain the process of case hardening.

Dave Lavery made two very informative posts about hardening stuff here and here.

[team222badbrad]

One inch diameter A2 tool steel is what we make the shaft with. The shaft and gears were hardened to between 55 and 62 Rockwell C.

Whatever you do, just keep them lubricated as with any transmission!

[EricH]

In 2003, we had a gearbox for our four-bar lift. We hit the bar across the field wrong two days before ship at a practice event and broke two teeth on one gear (non-treated). We exchanged it for a heat-treated gear and had no problems later.