Constantinesco Torque Converter in Lego
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- Опубліковано 25 сер 2024
- CVT means Continuously Variable Transmission. Unlike a standard transmission, which has several fixed ratios to choose between, a CVT has pretty much infinite ratios. This means smoother acceleration, better power delivery, and less loss of power due to shifting and clutching than a normal trans.
CVTs are nothing new. Dodge has a CVT ( • Dodge CVT Animation ) that's belt driven and uses variable pulleys. NuVinci has a bike hub ( • NuVinci Hub ) that uses swivelling balls and some kind of grippy fluid. Simkinetics ( • Automatic Bicycle Tran... ) has a pretty interesting design as well, which looks quite similar to this design except that it uses cams (?) instead of pendulums.
I like this design because it's relatively robust. It doesn't need special fluids, it doesn't rely on friction, and even in Lego it works pretty well. There may be a better design out there (the Simkinetics hub looks promising), but this system seems like a good place for me to start tinkering.
To see the Wikipedia write-up on what I'm trying to replicate, go here: en.wikipedia.or...) or here to read about the inventor en.wikipedia.or... or here commons.wikimed... for the pics I worked from.
I built this from two Lego Mindstorms kits (1.5 and 2.0), one Ultimate Accessory pack, a few bits from some monkey kit thing, and a few other bits and pieces I had laying around. Your mileage may vary depending on what parts you have at your disposal. None of the parts were modified, and the only non-Lego part is the string.
Questions/comments welcome.
Thanks for the video, very... explanatory. As for the Constantinesco torque converter, it was used in some Malaxa switching locomotives and rail cars of the 1930's and 40's (id I'm not mistaking), some of which can still be found in use today.
Constantinescu realized the importance and power of the pendulum by emphasizing its main use. The great problem of understanding that technology comes from our schools, universities, and physics itself diverting us from studies of pendulums and the misconception that centrifugal force is a virtual force. Then Constantinescu understood these two characteristics and applied them in a device. The secret is in the pendulums, there is no contact between the device and the ground through transmission. The pendulums, when they oscillate in their arc-shaped trajectory, develop a centrifugal reaction (physically speaking) which pulls the object in which its center is fixed. In the patent 1,715,816 (rexresearch.com/constran/1constran.htm) (Figure 1) you will see an inertial mass 4, it is only on the left side, but there has to be another one on the right side, the horizontal bar (11) below connecting the lower end of the rod holding the inertial mass is in the wrong position. Now imagine another rod with an inertial mass on the right side, notice that it fits perfectly into the part (10). Then the horizontal bar 11 will be connected at point 6 of the rod we placed on the right side, the horizontal bar will now be tilted. The steering wheel serves only to soften the leaps caused by the changes of direction of the two pendulums. So when one pendulum goes to the left, the other goes to the right. By way of illustration, a 1.6 liter car weighing 900 kg goes from 0 to 100 km / h in 11.03 seconds, during this time its engine develops a force of 2,400 Newton equals a mass of 243.40 kg, now see the following, if you take an object of mass equal to 0.25 kg, 250 grams, attach it to a string of 15 centimeters and rotate at a rotation of 1200 rpm, you will have a centrifugal force of 592.17 Newton, this will be the constant force that the 0.25 kg object is subjected to during rotation. If it were possible to place a scale under the object it would register a mass increase and this value would be 60 kg. It turns out that in a rotation of 1200 rpm the object will pass 20 times in 1 a second, then the force centrifuged in any degree of a circumference will be of 11.843,40 Newton which is equivalent to a mass of 1201,15 kg.
But on a circumference it is impossible to take advantage of this misunderstood force and magnify that it is the centrifugal force, for now the centrifugal force is on the left, or on the right, sometimes above and below, but with a pendulum this does not happen.
Place this whole set horizontally. The pendulum is to be used horizontally, because the physical phenomenon that Constantinesco used was the centrifugal inertial force. In its mounting position, the centrifugal inertial force is in the downward direction.
Calculate the force present on a pendulum at a given oscillation. Bend the swing of the pendulum and recalculate the centrifugal force. Then imagine a mechanism to make the pendulum swing at the desired frequency. Ready. The mechanism of Constantinesco is made. The focus should always be the centrifugal force.
I built one like yours in metal in a 1963 school science fair along with a mechanical analysis. I got second prize in technology because not everyone understood it! Haha! The railcar versions used an oscillating flywheel instead of the pendulum. A rocking arm was fixed to the flywheel at ,say, 60% of the radius with input on one end of the rocking are and the output taken from the other end. As others have commented roller clutches are more effective but I also used ratchets as you did. Nice job!
Bill Radford
In 1963 I had just been born, Hahaha. I imagine it was very difficult or impossible for you to register your mount at that time. Regarding the versions of the wagon, I believe you were mistaken, Constantinescu realized the importance and power of the pendulum by emphasizing its main use. The great problem of understanding that technology comes from our schools, universities, and physics itself diverting us from studies of pendulums and the misconception that centrifugal force is a virtual force. Then Constantinescu understood these two characteristics and applied them in a device. The secret is in the pendulums, there is no contact between the device and the ground through transmission. The pendulums, when they oscillate in their arc-shaped trajectory, develop a centrifugal reaction (physically speaking) which pulls the object in which its center is fixed. In the patent 1,715,816 (rexresearch.com/constran/1constran.htm) (Figure 1) you will see an inertial mass 4, it is only on the left side, but there has to be another one on the right side, the horizontal bar (11) below connecting the lower end of the rod holding the inertial mass is in the wrong position. Now imagine another rod with an inertial mass on the right side, notice that it fits perfectly into the part (10). Then the horizontal bar 11 will be connected at point 6 of the rod we placed on the right side, the horizontal bar will now be tilted. The steering wheel serves only to soften the leaps caused by the changes of direction of the two pendulums. So when one pendulum goes to the left, the other goes to the right. By way of illustration, a 1.6 liter car weighing 900 kg goes from 0 to 100 km / h in 11.03 seconds, during this time its engine develops a force of 2,400 Newton equals a mass of 243.40 kg, now see the following, if you take an object of mass equal to 0.25 kg, 250 grams, attach it to a string of 15 centimeters and rotate at a rotation of 1200 rpm, you will have a centrifugal force of 592.17 Newton, this will be the constant force that the 0.25 kg object is subjected to during rotation. If it were possible to place a scale under the object it would register a mass increase and this value would be 60 kg. It turns out that in a rotation of 1200 rpm the object will pass 20 times in 1 a second, then the force centrifuged in any degree of a circumference will be of 11.843,40 Newton which is equivalent to a mass of 1201,15 kg.
But on a circumference it is impossible to take advantage of this misunderstood force and magnify that it is the centrifugal force, for now the centrifugal force is on the left, or on the right, sometimes above and below, but with a pendulum this does not happen.
@caesareor Thanks. Yeah, torque would be an issue, unless the motor was really slow. Given the idle speed of a gasoline engine, it would need a clutch to stop it from fighting against the handbrake. In fact I think I'd set up a CVT much like a standard auto trans, with the torque converter feeding a few clutch packs. This would also provide for underdrive gears and reverse.
I've dismantled this one to attempt a dual-pendulum setup. I'll try slow input with that one if I get it working.
Thanks! Yeah, I think the real deal would have two pendulums to smooth out the rough spots. I tried making a dual-pendulum model, but I couldn't keep the pendulums synced... between the limitations of the Legos and the limitations of the design, I couldn't get it to work consistently.
I haven't built one of these, but, I'd wager that the trepedation is caused by coarse-grained ratchets. If you use smaller teeth spacing (or multiple offset ratchets), you can get smoother output.
I used the standard geared pre-NXT motors. I ended up using two to get the torque I needed to push the bulky pendulum stuff, so a direct-drive motor probably wouldn't do much good here. Thanks though!
Thanks for video. I need to build one to convert torque from my Free Piston Stirling Engine.
Completely irreverent, but I've won a few bucks in bets with people thanks to this torque converter. Rest the handle of a broom on the ground, bristles up. Have someone grab a few inches from the bottom, and start to *gently* sway the broom, while keeping the tip in place. Ask them to try to speed their sway without moving the tip. It won't be long before they can't keep the tip in place, and they'll break a sweat trying.
A great way to get hands-on appreciation for the device. :)
Cool prototype! I wonder, though, about the torsional trepidation at the wheel. I can see in the video that the wheel's rotation is kind of jerky which I suppose is a direct consequence of the one-way clutch. I don't mind the shaking of the entire frame, as the pendulum's motion is obviously not balanced, but I think the torque fluctuations at the wheel (the jerkiness) are harder to eliminate as they are a result of the one-way clutch. What do you think? Keep it up, it's really cool!
good work,d have you checked out the rexresearch page on him yet?
Hey man, nice build. Anyway, I was wondering if you can adjust the motor rpm. I would be curious to see what happens at lower rpms .
My concern is that if you reduce the rpm's to 1/4 let's say (the equivalent ratio between the drive and idle rpms in a real car) there will still be a lot of torque in that wheel so you would need quite a strong hand brake to keep a car stationary.
Now I know that the guy actually built the car and it worked fine but I would like to see it too. :)
the site is Rex research.com they have quite the story on him plus other good stuff
Likely! The real thing used much better one-way clutches with rollers. They should lock up more or less instantaneously. Mine... not so much LOL.
Knex automatic transmission MK4 CVT buggy very first run Knex pendulum automatic transmission in a solar powered car
amazing!
@boyd868b The what now?
There are subtle situations that would render this machine metallurgically impossible if built in large versions.
First of all, If ever a pendulum is driven at any other frequency apart from its natural resonance frequency it will absorb energy and the only frequency where it takes little energy is at its resonant frequency.
* Without the load being locked, ( free to rotate) in this case, at very very slow speeds while the load is well activated, the weight of the pendulum may swing a little depending on the load. At resonance with the load not locked well, I would say that it would swing much more . Above resonance the high inertia of the pendulum will keep it almost still, while the load will take its full share of the movement..
* With the load locked , the pendulum will come into action and as far as the forces on those push and pull transmission rods, they will be great, except at resonance frequency of the pendulum. If the energy in the motor is not reduced then at resonance the pendulum will try and rotate rather than oscillate.
An interesting machine in such dimensions but not larger ones, congratulations.
It turns out that this was one of the first patents of Constantinescu, it evolved into a purely inertial system, the wheels of the car are like wheels of skateboards, free.
Constantinescu realized the importance and power of the pendulum by emphasizing its main use. The great problem of understanding that technology comes from our schools, universities, and physics itself diverting us from studies of pendulums and the misconception that centrifugal force is a virtual force. Then Constantinescu understood these two characteristics and applied them in a device. The secret is in the pendulums, there is no contact between the device and the ground through transmission. The pendulums, when they oscillate in their arc-shaped trajectory, develop a centrifugal reaction (physically speaking) which pulls the object in which its center is fixed. In the patent 1,715,816 (rexresearch.com/constran/1constran.htm) (Figure 1) you will see an inertial mass 4, it is only on the left side, but there has to be another one on the right side, the horizontal bar (11) below connecting the lower end of the rod holding the inertial mass is in the wrong position. Now imagine another rod with an inertial mass on the right side, notice that it fits perfectly into the part (10). Then the horizontal bar 11 will be connected at point 6 of the rod we placed on the right side, the horizontal bar will now be tilted. The steering wheel serves only to soften the leaps caused by the changes of direction of the two pendulums. So when one pendulum goes to the left, the other goes to the right. By way of illustration, a 1.6 liter car weighing 900 kg goes from 0 to 100 km / h in 11.03 seconds, during this time its engine develops a force of 2,400 Newton equals a mass of 243.40 kg, now see the following, if you take an object of mass equal to 0.25 kg, 250 grams, attach it to a string of 15 centimeters and rotate at a rotation of 1200 rpm, you will have a centrifugal force of 592.17 Newton, this will be the constant force that the 0.25 kg object is subjected to during rotation. If it were possible to place a scale under the object it would register a mass increase and this value would be 60 kg. It turns out that in a rotation of 1200 rpm the object will pass 20 times in 1 a second, then the force centrifuged in any degree of a circumference will be of 11.843,40 Newton which is equivalent to a mass of 1201,15 kg.
But on a circumference it is impossible to take advantage of this misunderstood force and magnify that it is the centrifugal force, for now the centrifugal force is on the left, or on the right, sometimes above and below, but with a pendulum this does not happen.
i knew he was a nerd :P