D-drive engineering Friday challenge

[mordred]

http://www.gizmag.com/steve-durnin-ddrive-d-drive-infinitely-variable-transmission-geared/15088/

here is a non programming Friday challenge figure out how this this works

and no I haven't figured it out eyt either thought it would peak some interest though

 

[quadPLC]

That is amazing. While I am not a mechanical engineer, certainly that looks to be an effective system at that scale.

Let's see how it fairs when it is brought up to handle substantial real-world torque levels in a car.

 

[ndzied1]

I would call it genius. Simple components combined in a novel way to achieve a new effect or output...

Hat's off to Mr. Durnin!

 

[kamenges]

I think it is effectively this with an electric motor in place of the variable pitch pulleys and chain. It's also the basis of the power coupling of the Toyota Hybrid Synergy Drive. It will be interesting to see how much energy you will need to put into the speed control input when it is under load.

Keith

 

[Paul B]

mordred - great thread! I enjoyed your link. Looks like a pretty cool site overall.

 

[monkeyhead]

It will be interesting to see how much energy you will need to put into the speed control input when it is under load.

I was wondering the same thing. In the video, they claim it's a relatively small amount respective to the input power. It's a neat concept though.

Hopefully the inventors claims to 'an order of magnitude' more efficient than a friction based system are true.

 

[Tom Jenkins]

The embodiment is new, but the fundamental concept of a phase shifting differential isn't. They've been used in the printing industry for a long time:

http://www.directindustry.com/prod/vogel/differential-9352-400503.html

I hope he is on to something, though. I'm interested to see how the testing fares. After all, the first law of thermodynamics can't be violtated! (Conservation of Energy, you know!)

 

[Clay B.]

To me if it works the main savings will be in clutches and matching the transmition to the engine

As Tom said I have seen something similar on offset printing presses to control roller speed.

Got to admit I never thought about using it the way he shows. It will be cool if it works.

 

[bernie_carlton]

You may have seen in the follow-up reports that the system won't behave as described. As the power is ramped up the 'control' has to have the same power as the 'main' input. They are mechanically equivalent in providing power to the output. In fact the system under an output load would backdrive whichever is the weaker input ('main' or 'control') drive. Ah well ...

 

[milldrone]

To me if it works the main savings will be in clutches and matching the transmition to the engine

If I'm understanding this drive correctly, the control shaft needs to be driven at exactly the same speed as the power input shaft to keep the vehicle motionless. I wonder how the accelerator pedal designers at Toyota would feel about this concept! Seems to me that the potential for a undesirable fail mode state would be inevitable.

 

[Eric Nelson]

If I'm understanding this drive correctly, the control shaft needs to be driven at exactly the same speed as the power input shaft to keep the vehicle motionless. I wonder how the accelerator pedal designers at Toyota would feel about this concept! Seems to me that the potential for a undesirable fail mode state would be inevitable.

Hehe, I was showing a friend this video, and we had the EXACT same thought. If you lose the control input, it goes straight to full speed!...



-Eric

 

[Mickey]

Hehe, I was showing a friend this video, and we had the EXACT same thought. If you lose the control input, it goes straight to full speed!...



-Eric

That's why they make these.

 

[rdrast]

You may have seen in the follow-up reports that the system won't behave as described. As the power is ramped up the 'control' has to have the same power as the 'main' input. They are mechanically equivalent in providing power to the output. In fact the system under an output load would backdrive whichever is the weaker input ('main' or 'control') drive. Ah well ...

Without seeing anything exceptional, I have to agree with bernie here 100%. With the gearing I'm seeing, it looks like the PTO available energy is just the sum energy of the prime mover and the (secondary) prime mover.

The simplest case is reverse. In reverse, all the energy is being supplied by the "Control" motor, which means it needs to be sufficiently sized.

It seems just an elongated version of Toyota's synergy drive, which acts exactly the same way, and also has no clutch or friction plates, except for reverse, the ICE is completely disabled, and the AC Motor (mounted directly between the drive axle and the PTO of the Synergy transmission) supplies all of the energy required to back the vehicle up. Sure, on the Synergy drive, you could keep the ICE running, and play with it's control motor (MG2, the DC motor/generator) to achieve reverse, but it's inefficient and pointless.