pic: Team 948 2-Speed Ball-Shifting Gearbox CAD Drawing

[team222badbrad]

Originally Posted by jfelser

Awesome video badbrad!! It explains the transmission very nicely. One question: How deep do the slots for the balls in the shifting gears go? A full 5/32? Or less than half of the bearing. It seems that slightly less would be the way to go, maybe 1/4 inch deep into the gear with a 5/16" EM (our design uses 5/16" bearings as well). I would think that the balls would disengage easier.

Sorry for taking so long to get back to you.


How far the balls will protrude out of the shaft depends on the diameter of your "Ball Plunger" + two times the diameter of your balls - the diameter of your shaft.

If your plunger is .515" and your balls are .3125", then your slots must be atleast 1.14" from tip to tip. Each ball upon being "Locked" would travel .07" above the shaft if your shaft is 1".

1/4'' = VERY BAD!!! If your balls were to travel past halfway above the shaft your shifting transmission would then become a single speed or perhaps shred to pieces. The balls would become trapted between the gears slots and shaft because of the rotational forces you put on them.

This attachment should help you out.

77 thousands is plenty as thats what the motorcycle transmission I used in the video had.

[jfelser]

Ah, thanks very much for the warning!!!

There is a very good chance you'll be seeing a transmission like this on NRG's robot this year... we talked to our machine shop about it a week or so ago, and they were very optimistic about the design.