Lego Technic smoothly switching 2 speed automatic gearbox - with instructions
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- เผยแพร่เมื่อ 10 พ.ค. 2024
- This video presents a smoothly switching 2 speed automatic gearbox made out of Lego Technic. The gearbox uses the "differential jam" phenomena to prevent reverse torque transmission during the gear switch over point, when the driving gearing can be momentarily disengaged.
The gearbox automatically switches down by a ratio of 2/3 when the load on the output is sufficiently high by using a differential to detect the loading and to drive an orange rotary catch (first introduced in the Lego Technic Bugatti 42083). This is a smooth transition due to the reverse path being only one directional.
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VISIT: technicbrickpower.com
INSTRUCTIONS: rebrickable.com/mocs/MOC-5103...
#technicbrickpower, #legotechnic - วิทยาศาสตร์และเทคโนโลยี
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Very interesting inline design !
Thanks happy to hear you like it. I think it can be improved though 🙂
Thanks for making this fantastic video and sharing your design. I appreciate it!
3:30 - spur gear equivalent to the Torsen helical design used in Audi differentials
Hi Jessica. Thanks for that - I will look it up!
@@TechnicBrickPower - no problem. The reason the opposite side can't drive the diff:
The countershaft reverses the rotation and is attempting to transfer the rotation back into the opposing member of the differential. Because the opposing member rotation is already reversed of the the input, it conflicts with the mesh of the countershaft.
A torsen diff works the same way to distribute torque between two output shafts. They work on the principle that worm gears can drive, but can't be driven. This is the opposite, in that your secondary output can be driven, but can't drive the unit.
@@jessicacopeland1644 Thanks! I had to read that a few times and watch the video to see what you meant and I get it now! Said a different way: The black shaft and yellow shaft are locked together by the gear train outside the differential. When you rotate the black shaft, the gear train keeps it locked to the yellow shaft and it works because everything is rotating in the correct direction. Note that the red shaft MUST turn in the same direction as the black shaft when the black shaft is turned with this setup.. If you try to turn the red shaft, since there is no gear train locking it to the yellow shaft, the differential tries to turn the black shaft in the OPPOSITE direction and that force is transmitted through the gear train to the yellow shaft in the wrong direction and the system is bound. Genius.
Brilliant thanks. Very clever and interesting video.
Genius design!
Glad you like it Blacktown.
It’s the speed and direction difference between the input to output along the lines of gears. One way is going from the outside of the dif and the other way is going from the middle. I hope you can see what I meant for I like what you have made
This is way beyond my scope of knowledge but very cool
Hi Sean - don't worry watch and learn - it's not as hard as you think.
@@TechnicBrickPower thanks man
Dude thr animation in the start jist kills it man. Thought it does go through the parts
Hi yeah not easy to animate a proper build...but might try it one day!
fascinating!
Hi Carl, Thanks - glad you liked it! Check out some of my other 2 speed gearbox videos if you like. 😀
@@TechnicBrickPower I'd love to add an auto box to my Lego monster truck! Will be investigating the options. I have no shortage of power and rather an excess of torque, have had to gear low to prevent melted axles. Plus I have 112mm tyres on my portalsz which twist the axles a lot... but your idea would.be cool in it 👍.
@@TechnicBrickPower I've had to watch this again, and I've ordered a job lot of diff and axle components, arriving next month! I like the fact that the diffs are used as an integrator, and sensor. The one way diff locking seems key to adding power without losing drive. Oh, and Happy Christmas!
@@carlbModels Hi Carl. I love ordering new parts. Hope this design works well for you and good luck with your projects!
I wonder if 3rd and 4th gears could be added with additional stages added on. However there might be more trickery needed such as each stage making sure all other stages are disengaged before engaging. And / or ratios must be different enough so they don’t fight against each other.
Awesome!!!
Thanks! It could be better. I will post build instructions on rebrickable sometime ... bet your parts haven't arrived yet 😄
Yea they will arrive in two months
This is akiyuki-level mechanical design
Hey thanks for the compliment! Hope you like some of my other builds.
Very interesting. Would be interesting to see that incorporated into a lego dump truck, construction vehicle, 4x4, 6x6 or similar and see in action. See if it would change gears with heavy loads.
Hi Ken, Yes I will try it in a prototype truck sometime. I have found some of my automatic gearboxes fail under heavy load. 🙃
@@TechnicBrickPower it qas only a thought. I'm surprised lego hasn't got hold of your isea and implemented it
That is pretty nice! :o
But I'm not sure if I understood it correctly, so one question:
If you increase the load on the the output the red differential has to work against the rubber band and rotate the orange switching wheel. Doesn't this mean, that while there is no state where no gear is engaged, there is a range of force where the second gear is used but the switch is not fully enganged?
Hi Tasse, thanks for your question. Yes the whole point of this design was to avoid the "disengaged intermediate state" which causes loss of traction or gear crunching. So in this design the final output is made up of the sum of a permanent speed plus another speed set by the gear selection. In the 1st gear this is simply zero by having that axle disengaged (and the one directional diff prevents loss of traction). The when then torque is high enough the orange selector is activated by the differential and selects another speed to add to the final output. I guess if the switch is not fully engaged then the additional force/speed is not fully added to the final output until the engagement is complete, however it still avoids losing traction on the overall output.
@@TechnicBrickPower Thank you! :) I think the force/speed would be fully added but the small contact area would be under heavy load. Maybe add a rubber 2L "thing" as a "limited ratchet" that can only be passed if the force is strong enough for a full switch. So it get's more binary an less continous.
Do you have an idea why does the one-way setup at 4:32 work? I'm clueless. In the first situation the left input rotates at speed 1, the differential has to rotate at speed 1/3 (due to the gear ratio between them) and the right input has to rotate at speed -1/3 (due to the differential equation (A+B)/2=C). When you rotate the gear connecting between the left input and the differential (second situation) it's basically reversed situation 1. But when you rotate the right input axel at speed 1 (third situation), the differential should rotate at speed -1 and the other input at speed -3. For some reason it doesn't. It must be similar to the wormgear-gear connection , the angle is maybe important.
HI 9/8. Actually no I don't have a satisfactory answer. All I can put it down to is a combination of the gearing ratio (3:1) and friction. However there is no problem driving a 3:1 with regular gears. Somehow the differential configuration exacerbates the friction to the point that is can no longer turn. I was surprised when I found that simple way of doing it to reproduce the same effect. Obviously if there was no friction then it should turn in reverse. Maybe there is some flexing in the plastic that is adding to the problem. I am plan to investigate it further it the future. 🙂
@@TechnicBrickPower did you find an answer? i can't figure why it stucked
Do you think this design is strong enouth for a my lpe v8 which is about as strong as 10 lego l motors?
LOL no way!!
what did you make that animation at the start with??
Hi Devlin - I use "Studio" from bricklink. 🙃
Do you know how to make an automatic 4 speed? I am making an off road car, and I would love an automatic 4 speed. If not, then no worries.
HI Max, I have focused mainly on 2 speed automatics - they are hard enough for me. But I am sure some of the ideas can be reused. In the future I hope to create 3 and 4 speed automatics so keep an eye out ;)
@@TechnicBrickPower Alright! No worries at all. Happy building!
I think you could just put couple of these in series. I'm not sure if the total friction is worth it. As you start adding total count of gears the total throughput goes down pretty fast. For original Lego Control+ motors, 2 or 3 gears might be optimal because you can manipulate the rpm pretty nicely and need lower gears only for higher torque.
do a 5 speed smooth change!!!
I have enough trouble with a 2 speed. Maybe I should try 1 speed! 🙃
WTF. Does it works in reverse ?
Hi Frederic, No it doesn't work in reverse - however it can be modified to do so. Its length will need to be increased by one. 😄
Cool thing
It look so wrong with orange and brown in it .. Lego why the ****
Thanks Niemand, but I like it. Welke kleur heb je liever? 🙃
@@TechnicBrickPower sry i am from austria but i understand it a bit(Similar language)
I am fan of good old Light Blurish gray and Black... that gears are red is fine since red is really common... Yellow makes no sense only in Yellow sets.. and Orange.. there is no good set which has orange in it... and even then not so many of them :|
Hi Niemand - thought you might have been Dutch with that name LOL. Yeah colour preferences are a bit personal but I try to choose some extreme colours to make the model stand out a bit otherwise each youtube thumbnail is a grey & black build. I am not a big fan of reddish-brown either to be honest but I had the pieces...so I used them. Oddly enough it is now my video with the most views so someone likes it!
@@TechnicBrickPower yea the idea is great and overall good editet so if you keep this you might can outperform the algorythm.. yea
-Niemand ist Deutsch und Niederländisch zugleich mit der gleichen bedeutung
@@TechnicBrickPower you know whats sad.. i have the red crane frol 2018 or 19 here... unfinished... i get so depressed to see a good set... just with so many useless colours
The input is actually what you are calling the output. The differential has ONE INPUT and two outputs. You're using it wrong.
Hi Protoborg. Thanks for your comment. I normally think of a differential as having two inputs and one output because you need to drive two in order to determine the 3rd. I guess you're thinking of how it is used for vehicle back wheels - yes then you have one input and two outputs, and the ratio of the outputs is determined by the force on the wheels or turning radius. Not sure if I am using it wrong as they seem to work fine for me!