Dewalt Shifting

Technical Technical Discussion
1

Team 1718 just finished their first prototype of a “Dewalt” style transmission with a cim running into it.

We currently don’t have a servo hooked up to it.

It is difficult to shift between gears one and two by hand - so much so that I doubt a servo could do it.

In addition, when we shift into “third” gear, the transmission freewheels. I haven’t torn it apart and figured out why - I’m assuming the freewheeling is expected since we removed the last ring gear to mount the cim per the NBD whitepaper, however I am concerned over how stiff the shifting is.

Is this normal, or are there tricks to making it shift easily that aren’t in the whitepaper? Or did we do something wrong…

2

It sounds like you may have forgotten to remove some of the mechanisms inside that transmission housing that keep it locked into gear. There are springs around the housing that act a bit like detents and make it difficult to move the shifting ring.

If done correctly, you should be able to freely shift from 1st through 2nd and into 3rd without any change in resistance – aside from waiting for teeth to engage.

Also, 3rd should not freewheel.

3

Thanks! Now I know I need to get inside it and find out what’s going on. It’s probably all related back to the same issue.

I’ll chase it down.

4
5

Thanks Stephen, that’s one of the first things I did before even reading your post - I didn’t see the point of having the detent spring when the servo was handling position.

I have a feeling this has more to do with us taking apart the transmission repeatedly to learn how it works. We probably just put something back in wrong.