Differential from 2 old angle grinders: Easy n Cheap

Logic11

100 mW
Joined
May 2, 2022
Messages
42
Hi guys :)
Been lurking and learning here, for a project I have in mind.

One of the things everyone building a quad or a delta trike wonders about is differentials.
Very simple (and damn clever!):
[youtube]cd1rcL7TiY0[/youtube]

Personally I'd enclose the diff/gap in the vid, fit sealed bearings, and drill/tap an oil filler hole.

I note that putting 2 small (springless?) centrifugal clutches in the pinion gears will give off roaders a limited slip differential.
Question is; where to source such..?

If you really wanted to get technical; you could even fit 2 small generators/motors to the pinion gears, with brushes around the shaft/s and get regen and limited slip every time you turned a corner! :)
But then you'd have turned a coil around the top of your shocks, placed magnets on arms and be regen-ing from every pump in the road too and I don't see anyone doing that!? :D


This crowd makes small diffs and many other interesting bits and bobs:
https://shop.sdp-si.com/catalog?cid=p130
 
Logic11 said:
One of the things everyone building a quad or a delta trike wonders about is differentials.
Very simple (and damn clever!):
[youtube]cd1rcL7TiY0[/youtube]

Hmm.... I wonder how much torque it would take (assuming cheap grinders)?

Given the cheapest peerless type diffs I've found start at $150 and go up from there, it may be worth looking up cheap craigslist grinders (the catch is the gearboxes are usually what fail, in my experience...so they may not be worth getting for this).


I've been wanting (for at least a couple of years) to do a version of my SB Cruiser using a peerless type diff and a frame-mounted motor (possibly QS205 50H, because I have it), rather than the hubmotor wheels I've been using (relatively successfully) for a few years now.

Partly to cut the weight down (it's a heavy cargo trike so it's already heavy even before cargo). Might be able to take 1/3 of the motor weight off (take off one motor but add the diff & axle).

Partly to enable gearing the motor itself down to optimize it for the speed I go to get the most possible torque for startups out of it.

Partly to make it easier to deal with flats and the like; I could just carry a spare wheel instead of having to do roadside patches or changing of tubes, etc. (would be much much easier in the intense summer desert heat).

And also to allow using much larger wheels for a better ride (29", for instance, vs the ~21"/22" I'm using now...which don't deal nearly as well with the potholes and poor road edges around here, which I can't always avoid). I could use bigger wheels now, but it would mean worse torque than I have now, and I need more, not less.
 
amberwolf said:
Hmm.... I wonder how much torque it would take (assuming cheap grinders)?

Well if you have a lathe or access to one; you can turn a casing that takes 3,4 or even 6 pinion gears.
But then you do need 3,4 or 6 old grinders.

https://build-its-inprogress.blogspot.com/2013/03/another-differential.html

Or you could buy new gears loose. I see there's plenty to choose from on the net.
Straight cut will be more efficient and as the gears only turn (and very slowly) when you are going around a corner, they arent going to be noisy.
But there is generally less gear contact surface = weaker and faster wear.
No idea which supplier uses quality tempered steel though.
 
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