Epic New Transmission? No Friction! Is it perfect?

[stovie]

actually cujet that is not even close to prius's transmission it's completly different from the prius specs and also he doesn't need a electric shifter motor in the tranny for that design all he needs is to have a braking devise in each shaft and slow the bottom 1 down for forward and the upper 1 for reverse and have both open for neutral because ur on the brakes witch will cause both shafts to spin anyway and power can only be pushed through by slowing 1 shaft or the other

[Automcdonough]

i like it. regardless of the actual efficiency numbers, it's advantages of simplicity, smoothness, and lack of slip are obvious.

[Frank Lee]

Pretty cool, pretty interesting, but I have doubts as to whether it really is the most efficient option for much equipment for example, existing bicycle chain drive is pretty tough to beat. D-Drive has plenty of gearsets in comparison.

[Rokeby]

I would say that this "transmission" is sufficiently similar to the Prius' Power
Split Device, PSD, that the "inventor" will need whole bunch of lawyers to
defend any claim that it is new and different. Ford has a similar if not
identical unit in its hybrid and shares a cross licensing agreement with
Toyota.



Photos of the PSD aren't really helpful in seeing its innards/workings as it's folded back on itself:



Ford went to great expense and complexity -- three clutches IIRC, with
possible long-term reliability consequences -- to ensure its version is not
similar. After bashing Toyota/Prius for so many years, it seems that GM
would rather shoot itself in the foot than admit to being wrong headed.

Here is an animated PSD simulator from the First Generation Prius with
variable inputs so that you can fiddle with it and see what happens:

Prius driving simulator

FWIW, the PSD has gone virtually unchanged through Gen II and Gen III, and
there is every indication it will appear in the PHEV in 2012.

IIRC, Toyota didn't invent it and pays royalties on the use of the design.

Frank Lee,

You probably already know that deep in the Prius' belly there is a drive chain.
Makes your heart go pitter-pat, don't it?

thanks a lot....

[Sulfuric]

There's friction. Unless they cool the tranny to near absolute zero and even then that's not going to work with a solid . . . but low friction is possible.

[eco_generator]

Interesting. It will need a quite sturdy case, and with all those eccentric orbits there will a few 1st and 2nd order vibrations to deal with.

[nitro-nige]

Originally Posted by NeilBlanchard

Straight (non-helical) gears cannot have all that great efficiency. Helical gears are better, but there are still losses.

I would have thought a straight cut gear would be more efficient as it's not generating a axial thrust force like a Helical gear would.

One another note, I've seen this before and limiting factor to me is how to you create an efficient variable speed drive for the control shaft?
My understanding is the principle of it's operation is about relative speed of the main gears. Kinda like running on a train. Your relative speed to the ground is different to your relative speed to the train.

[NeilBlanchard]

I was misunderstanding the reason for helical gears; my mistake. Though I do wonder about the slight slip-back that happens as each tooth disengages and the next engages (on straight cut gears)?

[cujet]

Originally Posted by nitro-nige

limiting factor to me is how to you create an efficient variable speed drive for the control shaft?

With electric motor-generators and computerized control. Just like a Prius.