Posted March 25, 201410 yr 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 :)
March 25, 201410 yr Author 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.
March 25, 201410 yr 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, 201410 yr by DrJB
March 26, 201410 yr 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.
March 26, 201410 yr 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?
March 26, 201410 yr 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.
March 26, 201410 yr 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.
March 27, 201410 yr 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, 201410 yr by DrJB
March 27, 201410 yr Author 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 :)
March 27, 201410 yr 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.
June 8, 20159 yr 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!
June 9, 20159 yr 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.
June 9, 20159 yr Yeah... I will probably also cut the worm wheel... :D Nice compact solution... :) Edited June 9, 20159 yr by MaxSupercars
June 9, 20159 yr 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, 20159 yr by NXT45
June 9, 20159 yr 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!
June 9, 20159 yr 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
June 9, 20159 yr 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 ;(.
June 9, 20159 yr 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, 20159 yr by Stormbird
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