Hi there, thought I'd let you know, this video led me custom make a torsen differential housing purpose built to house Lego gears to allow for the torque sensing effect. I'm hoping to take the idea to the Lego company (if possible) after I can prove it functional with the prototype. I already had it working briefly, but the material and production process left the prototype so weak it gave under force, but I think the Lego company can fix that with proper casting and production. Wish me luck :D
wow its been so long since ive seen lego technics!! I had a class in school about 7 years ago (6th grade) and we had to build and program robots with them.
You did a great job on your build and w/ the video. The only thing worth nagging about is your statement that it locks. Torsen differentials don't "lock". They CONTINUOUSLY (sorry for the caps, just trying to emphasize) meter wheel rotation between the 2 axles. Torsens do not ever vary in their action. Don't let commentors confuse you by talking about the behavior of other differential types and using vocabulary that fits them. Little of that applies to Torsen.
@bagger2222 This is not an open diff. The two half shafts are linked together via worm gears which can only rotate when driven one way, meaning that it locks. If it were an open diff one wheel could stop spinning because it locks you can not stop one wheel, watch the video.. especially the elevated wheel drive off, only a locked diff can do this, and the part where the wheels are pushed onto the ground, on an open diff one wheel stops.
There is some slack in the design, it is LEGO after all.
@Parax77 studied it again.. you are right, its a locking diff. my bad. but it is still not quite a "limited" slip diff. it actually only works at 100% lock or 0% nothing in between. the reason why you can still make curves is that the gears and worms dont fit perfectly to eachother. it will though definitly lock 100% after a short time driving a curve. its still very interesting and it WOULD work if the worms had a higher angle... but i know, there is no such gear in lego. ;) keep it up!
@bagger2222 It does not lock on a curve no matter how long I leave it, because the worms can turn as long as they are equal and opposite, ie it will turn on the spot -10 +10 Drive input at 0 (equal and opposite) and it will turn on a corner +10 +30 Drive input at +20 (ie -10 and +10 on top of drive so still equal and opposite)
@Parax77 pick up your vehicle, turn on the motor and hold one wheel. if it was a real LSD you should feel a force trying to turn that wheel, but you should still be able to hold it while the other is turning. your diff though will lock 100% after a short time which is even shown in the vid. so you either cant hold the wheel anymore or the motor will blockade. feel free to try it again. :) what you will find out is that its impossible to make a real LSD from lego gears only. i´m sorry!
@bagger2222 Are you saying the a Torsen does not lock? This is not how I understand it. I am not aware of any clutching or bypass slip in a torsen design. I do not have access to one to test, I only have a viscous LSD on my lotus 7 which is a different design.
I agree it is impossible to make a perfect diff with Lego...
@Parax77 i got an audi quattro, so i have to know about it!^^ a torsen never locks 100%. the partly "locking"-feature it creates is caused by high friction between the gears inside and goes in line with the applied torque. it wont ever lock on slow acceleration.
LSD´s in general work basically like standard-diffs with high inner friction which causes the slip-limitation. there are pure mechanical ones like the torsen, viscous LSD´s, electronic supported ones and combinations of either of them.
@Parax77 i studied it again... it IS a locking diff. but still not quite a "limited" slip diff. it either locks 100% or 0%. nothing in between. the only reason it can still go through curves is that the gears and worms dont fit perfectly to eachother. it will though definitly lock 100% after short time. you can see it in the vid... the vehicles turnradius increases due to sliping wheels. it WOULD work if the the worms had a higher angle, but i know there are no such gears in lego! keep it up! :)
@SidewaysGts No an exact torsen is not possible in Lego, as they don't make the right shaped gear parts! In this version the worm meshing is synthesised by using two (offset) straight worm gears (which do not mesh on their own) with an idler in the middle.
thanks for your post, This Diff does lock though! In the video I tried to show this by lifting a wheel, which showed that the diff locked up, and the vehicle drove off. also I showed that when you vary the torque by pressing or lifting on one side (varying fricton) it stays locked up, and continues to turn.
The only way this diff does NOT lock is when it is cornering such that the proportion of speed on the outer wheel is equal to (but opposite) to the preportion on the inner wheel. ie if the vehicle travells at a speed of 10 the outer wheel is 11 and the inner is 9 (+1 and -1) or the outer is 12 and the inner 8 (+2 and -2) then the diff will allow this, and will NOT Lock. This was demonstarted in the video by the circling which shows the wheels turning at different (but proportional) speeds.
Hey - nice job! On you photos, where did you get the solid models for the lego parts? What modeling software did you use? Are you willing to post a model file?
Its modelled in LDraw there are many more pictures in my brickshelf link. You should be able to work out how to make it from the pictures, its fairly straight forward.
I would post the files but brickshelf won't authorise them. I'll see about sorting out some deeplinks!
What about repalcing 20 and 12 tooth gears with 24 and 8 ones, so the centar gears has less force to carry? The diff would have to be 2 studs wider though.
Yes it would reduce the force on the centre cog, it would also reduce the 'slop' but it does not fit inside (between the mounts) of the turntable so, as you noted, would need to be wider and hence would not be as compact. I think its a fair trade off.
Hey, i have a question. Can u make list of the parts and how to build this step by step?
Bitekpierwszy 1 month ago
Hi there, thought I'd let you know, this video led me custom make a torsen differential housing purpose built to house Lego gears to allow for the torque sensing effect. I'm hoping to take the idea to the Lego company (if possible) after I can prove it functional with the prototype. I already had it working briefly, but the material and production process left the prototype so weak it gave under force, but I think the Lego company can fix that with proper casting and production. Wish me luck :D
NiteReepa 4 months ago 2
wow its been so long since ive seen lego technics!! I had a class in school about 7 years ago (6th grade) and we had to build and program robots with them.
guitarplaya1234 5 months ago
da motor sounds like its either screaming or singing,funny
knightrider1545 5 months ago
exelent
Muttergurke 6 months ago
thank you!
DjGisME 6 months ago
cool
christo4477 8 months ago
You did a great job on your build and w/ the video. The only thing worth nagging about is your statement that it locks. Torsen differentials don't "lock". They CONTINUOUSLY (sorry for the caps, just trying to emphasize) meter wheel rotation between the 2 axles. Torsens do not ever vary in their action. Don't let commentors confuse you by talking about the behavior of other differential types and using vocabulary that fits them. Little of that applies to Torsen.
Cheers.
deezynar 9 months ago 3
thats a standard-diff... not even a selflocking!?
you are doing moves which a real LSD shouldn´t let you to! :S
bagger2222 10 months ago
@bagger2222 This is not an open diff. The two half shafts are linked together via worm gears which can only rotate when driven one way, meaning that it locks. If it were an open diff one wheel could stop spinning because it locks you can not stop one wheel, watch the video.. especially the elevated wheel drive off, only a locked diff can do this, and the part where the wheels are pushed onto the ground, on an open diff one wheel stops.
There is some slack in the design, it is LEGO after all.
Parax77 10 months ago
@Parax77 studied it again.. you are right, its a locking diff. my bad. but it is still not quite a "limited" slip diff. it actually only works at 100% lock or 0% nothing in between. the reason why you can still make curves is that the gears and worms dont fit perfectly to eachother. it will though definitly lock 100% after a short time driving a curve. its still very interesting and it WOULD work if the worms had a higher angle... but i know, there is no such gear in lego. ;) keep it up!
bagger2222 10 months ago
@bagger2222 It does not lock on a curve no matter how long I leave it, because the worms can turn as long as they are equal and opposite, ie it will turn on the spot -10 +10 Drive input at 0 (equal and opposite) and it will turn on a corner +10 +30 Drive input at +20 (ie -10 and +10 on top of drive so still equal and opposite)
Parax77 10 months ago
@Parax77 see youtube.com/watch?v=Hn0uSCmrNc8 this allows equal and opposite rotation only.
Parax77 10 months ago
@Parax77 type that v=Hn0uSCmrNc8 part! youtube link prevention inserts bad chars.
Parax77 10 months ago
@Parax77 pick up your vehicle, turn on the motor and hold one wheel. if it was a real LSD you should feel a force trying to turn that wheel, but you should still be able to hold it while the other is turning. your diff though will lock 100% after a short time which is even shown in the vid. so you either cant hold the wheel anymore or the motor will blockade. feel free to try it again. :) what you will find out is that its impossible to make a real LSD from lego gears only. i´m sorry!
bagger2222 10 months ago
@bagger2222 Are you saying the a Torsen does not lock? This is not how I understand it. I am not aware of any clutching or bypass slip in a torsen design. I do not have access to one to test, I only have a viscous LSD on my lotus 7 which is a different design.
I agree it is impossible to make a perfect diff with Lego...
Parax77 10 months ago
@Parax77 i got an audi quattro, so i have to know about it!^^ a torsen never locks 100%. the partly "locking"-feature it creates is caused by high friction between the gears inside and goes in line with the applied torque. it wont ever lock on slow acceleration.
LSD´s in general work basically like standard-diffs with high inner friction which causes the slip-limitation. there are pure mechanical ones like the torsen, viscous LSD´s, electronic supported ones and combinations of either of them.
bagger2222 10 months ago
@Parax77 i studied it again... it IS a locking diff. but still not quite a "limited" slip diff. it either locks 100% or 0%. nothing in between. the only reason it can still go through curves is that the gears and worms dont fit perfectly to eachother. it will though definitly lock 100% after short time. you can see it in the vid... the vehicles turnradius increases due to sliping wheels. it WOULD work if the the worms had a higher angle, but i know there are no such gears in lego! keep it up! :)
bagger2222 10 months ago
Question: If you connect the Power Engine, you always need to connect it to the left AND right axle? I am making my first diff. but it doesn't work.
TheJDWK 1 year ago
This is really cool, thanks for sharing this.
Squidalert 1 year ago
holy shit!!! ur great @ this!!! really cool, i now want one!
0012554 1 year ago
Not exactly a torsen lsd, but neat none the less
SidewaysGts 1 year ago
@SidewaysGts No an exact torsen is not possible in Lego, as they don't make the right shaped gear parts! In this version the worm meshing is synthesised by using two (offset) straight worm gears (which do not mesh on their own) with an idler in the middle.
Parax77 1 year ago
god, some seriouse shit right here
fatharmonix 1 year ago
very nice!
jhbonarius 1 year ago
i couldn't have even understood how torsen worked, you made a lego model of it!
any assembly instructions?
nlty2000 1 year ago
thats closer than some lsds but still not quiet there an lsd locks going forwards under torque cool build though
Sammanben 1 year ago
thanks for your post, This Diff does lock though! In the video I tried to show this by lifting a wheel, which showed that the diff locked up, and the vehicle drove off. also I showed that when you vary the torque by pressing or lifting on one side (varying fricton) it stays locked up, and continues to turn.
Parax77 1 year ago
The only way this diff does NOT lock is when it is cornering such that the proportion of speed on the outer wheel is equal to (but opposite) to the preportion on the inner wheel. ie if the vehicle travells at a speed of 10 the outer wheel is 11 and the inner is 9 (+1 and -1) or the outer is 12 and the inner 8 (+2 and -2) then the diff will allow this, and will NOT Lock. This was demonstarted in the video by the circling which shows the wheels turning at different (but proportional) speeds.
Parax77 1 year ago
Hey - nice job! On you photos, where did you get the solid models for the lego parts? What modeling software did you use? Are you willing to post a model file?
ormicElif 2 years ago
Its modelled in LDraw there are many more pictures in my brickshelf link. You should be able to work out how to make it from the pictures, its fairly straight forward.
I would post the files but brickshelf won't authorise them. I'll see about sorting out some deeplinks!
Version 2 is also hosted on my brickshelf.
Parax77 2 years ago
awesome!
sasop117 2 years ago
What about repalcing 20 and 12 tooth gears with 24 and 8 ones, so the centar gears has less force to carry? The diff would have to be 2 studs wider though.
Zblj1987 2 years ago
Yes it would reduce the force on the centre cog, it would also reduce the 'slop' but it does not fit inside (between the mounts) of the turntable so, as you noted, would need to be wider and hence would not be as compact. I think its a fair trade off.
Parax77 2 years ago
very nice work
Prollo87 2 years ago
nice
Parkourspeedster 2 years ago
nice work. looks compact and very sturdy
jorhoerst 2 years ago
THATS SICK !
joekinney 2 years ago