The D-Drive Infinitely Variable Geared Transmission
This brain-bending invention could be the holy grail of transmission technology – it allows you to smoothly move through gear ratios from top gear all the way through neutral and into reverse without ever disengaging the engine. Plus, there’s no friction drive component, so the power is always transmitted through gear teeth – there’s never any slip or friction losses.
In fact, the D-Drive’s main difficulty is that it’s so hard to understand that people don’t really know what to do with it. So here’s a close-up look, which will hopefully get a few people thinking.
Read the complete article here: http://www.gizmag.com/steve-durnin-ddrive-d-drive-infinitely-variable-transmission-geared/15088/ and a follow up to the response here: http://www.gizmag.com/d-drive-redux/15120/
Duration : 0:9:50
@aronsta: Pretty …
@aronsta: Pretty much, yes. As I and several others have commented on this months ago, this won’t work. As you’ve guessed, the electric control motor would need to generate torque equal to the max torque input in order to stop the control shaft (needed for full acceleration).
Isn’t this just an …
Isn’t this just an open differential with an electric motor on one of the outputs? If so, the torque on the motor and torque on the output shaft would be equal..right?
what if the …
what if the electric motor fails, it will go into full speed like a toyota. would be a lot better with a system of brakes to slow down the shafts
This is not an IVT! …
This is not an IVT! As CptLightning37 states, this is a PSD. For a true IVT, see my SIVAT; enter ‘Automatic Bicycle Transmission (IVT)’ into YouTube search. Also see IVT in Wikipedia. The IVT has only one input! Sorry Steve!
Please read before …
Please read before you go thinking this is amazing:
This is just a simple power splitter device, and contributes nothing new. The “control” shaft needs to be able to supply torque at times equal to the drive torque, and yet at variable speeds. Hence you’d need an actual cvt to be able to do this. Please srch google “d-drive redux” for gizmag acknowledging the error.
As mentioned by 79HZGTS below, a car differential does exactly the same thing, but less complex.
Don’t believe everything you see
@VacuumLogic,
Yes …
@VacuumLogic,
Yes they do. Look at a car differential. It has three input/output variables. There are two wheel hubs that turn independently of each other, and the tailshaft yoke. Any of these shafts can be used to “moderate” the relative angular velocity of the other two. Choose any one of them to be your primary input. The applied angular velocity of the second shaft will control the angular velocity of the third. It is also a lot less complex than this blokes planetary system.
Excellent !!!!!!!!! …
Excellent !!!!!!!!!! Well done Steve. I feel so stupid not to have thought of it myself. Looks like it has the potential to be shrunk down to say the size of a normal clutch housing. Less complexity, less weight, better efficientcy ot the transmition, and better efficentcy of the engine, truly the holy grail.
@Jarrah181086 In …
@Jarrah181086 In what way is this so? In a CVT, you can select the engine speed (e.g. the speed corresponding to peak energy output) and leave it there. Your speed is then controlled purely by the throttle and brakes. It stands to reason that the less variables controlling the cars acceleration, the less the driver has to take into consideration, and the better it can be raced.
Judging speed is …
Judging speed is pretty much all you do in autos, CVT’s, SST transmissions. A manual transmission provides more than this with greater control of the engine. Its not all about speed but also how and when the power and torque is delivered, thus providing greater control of the car. Get the out of your mouth and wake the up dumb tool.
@saiiko Small gears …
@saiiko Small gears is no problem, you just add more of them running the same speed. That is done in todays pulleys and is nothing special.
I would suggest you …
I would suggest you actually watch the video, this is a proof-of-concept model, not something that’s expected to be used in an automotive application. He notes several times that one designed for actual power transfer would be larger and would use all-metal parts.
1) If this was …
1) If this was implemented in a car, it would need a dedicated balancing system for the input cam gear,
2) The teeth in the sun/planet gear are too small to deal with huge torques expected in a normal car
Suggestions? Nice work though
i like his idea for …
i like his idea for some things like they said wind generators or whatever but i cant see that thing in a car. when he said bigger gears will take more torque thats when efficiency went out the window. i dont think we will ever see this in a motor vehicle on a street. maybe machinery tho
@79HZGTS Yes but …
@79HZGTS Yes but those devices don’t use the second bar gear moderator. Which is pure genius. You can infinitely variate gears.. the engine can even START WHILE ENGAGED.
I am not sure how …
I am not sure how he got his patent. Forty years ago, combat plotting tables on naval ships were using differential transmissions that worked exactly the same as this.
Anyway, if you take a differential out of any car, you can make it do exactly the same thing. If you turn both wheel hubs in a clockwise direction (looking at the hub) at the same speed, the tailshaft yoke will remain motionless. Speed up or slow down either hub and the tailshaft yoke will begin to turn one way or the other.
@kragsky
Listen …
@kragsky
Listen from 6.30 onwards
Looks pretty cool. …
Looks pretty cool. Gonna miss my manual transmission and clutch, tho.
@TheMarkus248 No, …
@TheMarkus248 No, it only needs to be strong enough to spin the cogs
@kragsky Hybrids do …
@kragsky Hybrids do – 1 engine, 1 motor. Did you even listen to the video? the motor can be tiny and be assisted by a flywheel
believe it or not …
believe it or not it’s that THAT hard to understand… physics people… study physics.