Zerobricks Posted March 25, 2014 Posted March 25, 2014 Thought of this diff yesterday night. Its quite compact, but only capapable to carry torque of an M motor... Still it works :) There are a totoal of 8 8-tooth gears to help spread the load and 2 worm gears. Its very easy to build, so I dare you guys to build it and try it out :) Quote
DrJB Posted March 25, 2014 Posted March 25, 2014 Wouldn't the construction be more compact/clean if you used only 4x 8t gears ? Quote
Zerobricks Posted March 25, 2014 Author Posted March 25, 2014 Wouldn't the construction be more compact/clean if you used only 4x 8t gears ? No, its same size, it would be shorther if Lego made shorter worm gears. Quote
DrJB Posted March 25, 2014 Posted March 25, 2014 (edited) Well ... I'm thinking a more robust construction with shorter beams, only 2 pairs of 8T gears, and the small turntable. Started doing that on LDD, seems feasible. Your design has 4 pairs of meshing gears around the circumference. This is done primarily to better distribute the load. You can however use only 2 pairs of meshing 8T gears, and these will be supported from both sides (hence my comment about sturdier construction). Edited March 28, 2014 by DrJB Quote
Zerobricks Posted March 26, 2014 Author Posted March 26, 2014 do you build lego at night? I built it in the morning :) Quote
Sheepo Posted March 26, 2014 Posted March 26, 2014 I designed a torsen diff some months ago. It is smaller than this. I will publish it soon, I want to make a complete video to show it, because a few people know what is a torsen diff. Quote
Hrafn Posted March 26, 2014 Posted March 26, 2014 I designed a torsen diff some months ago. It is smaller than this. I will publish it soon, I want to make a complete video to show it, because a few people know what is a torsen diff. I'm excited to see it! A lot of Technic LSD / Torsen / etc. diffs seem to have structural flaws, and some even tear themselves apart when subjected to large torque. Have you managed to avoid those problems? Quote
Sheepo Posted March 26, 2014 Posted March 26, 2014 I have tested it with 2 L motors with gear reduction, and it works really well. The main principle is the same as zblj with 2 worm gears and some 8t, but I have been able to place it in less space. Quote
Hrafn Posted March 26, 2014 Posted March 26, 2014 I have tested it with 2 L motors with gear reduction, and it works really well. The main principle is the same as zblj with 2 worm gears and some 8t, but I have been able to place it in less space. That's great! It sounds like both of these designs are true Torsen diffs, which is exciting. Some of the other LSD-type designs using worm gears have a sort of hysteresis or memory due to the way the worm gears travel. Quote
DrJB Posted March 27, 2014 Posted March 27, 2014 (edited) What I know about the Torsen differential is something very different than that presented here... unless there are many flavors. See link below: http://gillcad3d.blogspot.com/2012/08/torsen-differential.html The one I know of uses 45 degrees helical gears as main components (attached to left/right axles). Then, around such gears, are pairs of 2 worm gears + 4 spurs , at 2-3 locations min. Because of the 45 degrees helical gears requirement, I'm not sure a true Torsen is feasible in Lego. I'll do an LXF to illustrate. Edit: I see what you've done: You've combined the set of outer gears: instead of a helical worm gear and 2 spurs at each end, you've used a single spur, and simplified the construction dramatically. I wonder how the kinematics / torque differentil (left to right) get affected, by NOT using helical gears. The obe thing about such gears is that they're 'reversible' .... the one-tooth-worm from Lego is not ... Edited March 28, 2014 by DrJB Quote
Zerobricks Posted March 27, 2014 Author Posted March 27, 2014 I designed a torsen diff some months ago. It is smaller than this. I will publish it soon, I want to make a complete video to show it, because a few people know what is a torsen diff. Do show :) Quote
Sheepo Posted March 27, 2014 Posted March 27, 2014 I didn't want to show it before make the video, but here you have. Obviously it is nothing really new, just a more compact version of the tipical double-worm Lego torsen diff. Quote
Zerobricks Posted March 27, 2014 Author Posted March 27, 2014 Smaller with less gears yes Gonna try build it. Quote
brickified Posted June 8, 2015 Posted June 8, 2015 I didn't want to show it before make the video, but here you have. Obviously it is nothing really new, just a more compact version of the tipical double-worm Lego torsen diff. Hi Sheepo, did you ever post a video on this? I am curious how to build your Torsen differential. Thanks! Quote
Sylvian Posted June 9, 2015 Posted June 9, 2015 Thats very nice sheepo! sucks i dont have the small turntable. Wouldnt mind sacrificing a worm gear to make the narrow version. Imho the best way to make a small lsd i've seen so far. Quote
MaxSupercars Posted June 9, 2015 Posted June 9, 2015 (edited) Yeah... I will probably also cut the worm wheel... :D Nice compact solution... :) Edited June 9, 2015 by MaxSupercars Quote
NXT45 Posted June 9, 2015 Posted June 9, 2015 (edited) I didn't want to show it before make the video, but here you have. Obviously it is nothing really new, just a more compact version of the tipical double-worm Lego torsen diff. Removed large photo. Did you modify your small turntable? Edited June 9, 2015 by NXT45 Quote
PKW Posted June 9, 2015 Posted June 9, 2015 something useful for this thread: Torsen Differential, How it works ?: Quote
Gnac Posted June 9, 2015 Posted June 9, 2015 Did you modify your small turntable? It looks like the black half of an unassembled turntable with one of these inside for support. I have two mini turntables - both assembled - and very hard to get apart. So I won't be trying this myself just yet. Gah! Quote
Stormbird Posted June 9, 2015 Posted June 9, 2015 Hi there Theses parts can be bought disassembled ? Items For Sale: Dark Bluish Gray (23) * Technic Turntable Small Bottom Items For Sale: Parts: Technic Catalog Entry Items For Sale: Light Bluish Gray (6178) * Technic Turntable Small Top Items For Sale: Parts: Technic Catalog Entry Items For Sale: Black (4644) regards Paul Quote
Sheepo Posted June 9, 2015 Posted June 9, 2015 Thats very nice sheepo! sucks i dont have the small turntable. Wouldnt mind sacrificing a worm gear to make the narrow version. Imho the best way to make a small lsd i've seen so far. I though about that, but my purity about modify parts is more important than improve the diff. When I listened the first time that Lego would release a new worm gear I hoped the new worm will be 1L, but finally they released the almost useless 3L worm gear... ;( It looks like the black half of an unassembled turntable with one of these inside for support. I have two mini turntables - both assembled - and very hard to get apart. So I won't be trying this myself just yet. Gah! You are correct, I had the sme problem, all my turntables were assembled, I had to buy the black part of the turntable in BL because I couldn't disassemble it without broke it ;(. Quote
Stormbird Posted June 9, 2015 Posted June 9, 2015 (edited) Hi all Sorry but I am all lost on this type of differential ? I found this example and was able to build it , however ... The long shafts opposing each other need to be supported in a frame and are the outputs ? Do I drive one of the 40t gears ? Actually the one from here , it is wider however probably more robust ? http://www.brickshelf.com/cgi-bin/gallery.cgi?i=331500 regards Paul Edited June 9, 2015 by Stormbird Quote
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