high tech transmission

Dear Chris,
thanks for inviting me to get out from your thread.
I want to introduce you to my latest baby.
Dual Clutch 7 speed transaxle with 1.250 Nm of torque capability.
Centralised synchronisation ( all 4 are pre-synchronising together, if you understand the meaning )
Now probably you realise how far you are from disturbing me on that confortable planet.
Take it easy.
PLS CHECK ATTACHMENT

Dear Wanni,

Stop belittling people who are having a go.

Steve

Wanni

That gearbox looks very interesting - to an untrained accountants eye.

What is the reason for increasing the number of gears? Is it purely to give a lorer RPM at cruising or is it for some other technical reason?

I have heard that with the bigger RPM changes during gear change the syncro works harder but surely that is the syncros job. Unless this causes excessive wear or some other roblem.

As I say it all interests me but I am far below your technical skill and ability.

Thanks
Ian.

steve kulper.
I THINK YOU HAVE OVERSTEPPED THE BOUNDS.
YOUR LAST POST WAS DOWNRIGHT OFFENSIVE AND REDOLENT/TYPICAL
OF ONE OF 'MEATS' POSTINGS.
IMHO YOU SHOULD IMMEDIATELY RETRACT IT.

Steve,
Thank you for editing it. You have said just as much as your original post did.
Dave M

David,
done, didn't want to offend anyone.
Steve

Thanks Steve,
see my edited post above.

Wanni we now have many new transaxle alternaitves which is great. They are all different and have a place.

When you have more details about your we would all appreciated hearing about it.

Is it sequential - what is the LSD - size, mounting,cooling and not least price ?

I am still planning my build and waiting till all the new transaxle alternaitves sort themselves out before proceeding with ordering my kit. Sounds like it will be another year or two before they are out there and reliability has been proven.

Charlie

Max input torque: 1.250 Nm
Max output torque: 9.000 Nm with basic diff. and 11.000 Nm with active diff.
Max revolutions: 10.000 1/min
Impact factor constant: 2.00
Static weight distribution ( fully loaded ): front = 850 Kgs – rear = 1.000 Kgs
Centre of gravity height: 500 mm
Tyre grip: μ ≥ 1.5

The basic unit to start is a NON preloaded “ type TORSEN “ unit in order to keep safe and alive the NON professional drivers also on wet conditions.
The sophisticate unit is an “ ACTIVE TORQUE VECTORING “ unit which is in development in collaboration with a well known manufacturer of those matters.
The maximum traction is then guaranty from this unit by transferring instantaneously from a wheel to the other accordingly to the possibilities.

Out of the calculation data, it is easily understandable that the targeted vehicles are comfortably reaching a top speed in excess of 400 Km/h.
In order to have a gear spread taking care of the best performances, 7 speeds is the minimum necessary.

Short explanation about how it works, just feel free to link to…. howstuffworks.com….. as soon as you have read this reply until the end, and then look for DCT. This link will do it much better then me in order it is written in your mother tongue.
The single rail shifter is very useful during hard brakings giving the possibility to the gearbox management to jump gears during an energised change of vehicle dynamics.
Hands-On or Hands-Off
A dual-clutch transmission offers the function of two manual gearboxes in one. To understand what this means, it's helpful to review how a conventional manual gearbox works. When a driver wants to change from one gear to another in a standard stick-shift car, he first presses down the clutch pedal. This operates a single clutch, which disconnects the engine from the gearbox and interrupts power flow to the transmission. Then the driver uses the stick shift to select a new gear, a process that involves moving a toothed collar from one gear wheel to another gear wheel of a different size. Devices called synchronizers match the gears before they are engaged to prevent grinding. Once the new gear is engaged, the driver releases the clutch pedal, which re-connects the engine to the gearbox and transmits power to the wheels.
So, in a conventional manual transmission, there is not a continuous flow of power from the engine to the wheels. Instead, power delivery changes from on to off to on during gearshift, causing a phenomenon known as "shift shock" or "torque interrupt." For an unskilled driver, this can result in passengers being thrown forward and back again as gears are changed.
Drivers can also choose a fully automatic mode that relinquishes all gear-changing duties to the computer. In this mode, the driving experience is very similar to that delivered by a conventional automatic. Because a DCT transmission can "phase out" one gear and "phase in" a second gear, shift shock is reduced. More importantly, the gear change takes place under load so that a permanent flow of power is maintained.
An ingenious two-shaft construction separating the odd and even gears makes all of this possible. We'll learn about these two shafts in the next section.
Dual-clutch Transmission Shafts
A two-part transmission shaft is at the heart of a DCT. Unlike a conventional manual gearbox, which houses all of its gears on a single input shaft, the DCT splits up odd and even gears on two input shafts. How is this possible? The outer shaft is hollowed out, making room for an inner shaft, which is nested inside. The outer hollow shaft feeds second and fourth gears, while the inner shaft feeds first, third and fifth.
The diagram below shows this arrangement for a typical five-speed DCT. Notice that one clutch controls second and fourth gears, while another, independent clutch controls first, third and fifth gears. That's the trick that allows lightning-fast gear changes and keeps power delivery constant. A standard manual transmission can't do this because it must use one clutch for all odd and even gears.
Multi-plate Clutches
Because a dual-clutch transmission is similar to an automatic, you might think that it requires a torque converter, which is how an automatic transfers engine torque from the engine to the transmission. DCTs, however, don't require torque converters. Instead, DCTs currently on the market use wet multi-plate clutches. A "wet" clutch is one that bathes the clutch components in lubricating fluid to reduce friction and limit the production of heat. Several manufacturers are developing DCTs that use dry clutches, like those usually associated with manual transmissions, but all production vehicles equipped with DCTs today use the wet version. Many motorcycles have single multi-plate clutches.
Like torque converters, wet multi-plate clutches use hydraulic pressure to drive the gears. The fluid does its work inside the clutch piston, seen in the diagram above. When the clutch is engaged, hydraulic pressure inside the piston forces a set of coil springs part, which pushes a series of stacked clutch plates and friction discs against a fixed pressure plate. The friction discs have internal teeth that are sized and shaped to mesh with splines on the clutch drum. In turn, the drum is connected to the gearset that will receive the transfer force. Audi's dual-clutch transmission has both a small coil spring and a large diaphragm spring in its wet multi-plate clutches.
To disengage the clutch, fluid pressure inside the piston is reduced. This allows the piston springs to relax, which eases pressure on the clutch pack and pressure plate.
We'll look at the pros and cons of dual-clutch transmissions next.
Pros and Cons of Dual-clutch Transmissions
Hopefully it's becoming clear why the DCT is classified as an automated manual transmission. In principle, the DCT behaves just like a standard manual transmission: It's got input and auxiliary shafts to house gears, synchronizers and a clutch. What it doesn't have is a clutch pedal, because computers, solenoids and hydraulics do the actual shifting. Even without a clutch pedal, the driver can still "tell" the computer when to take action through paddles, buttons or a gearshift.
Driver experience, then, is just one of the many advantages of a DCT. With upshifts taking a mere 8 milliseconds, many feel that the DCT offers the most dynamic acceleration of any vehicle on the market. It certainly offers smooth acceleration by eliminating the shift shock that accompanies gearshifts in manual transmissions and even some automatics. Best of all, it affords drivers the luxury of choosing whether they prefer to control the shifting or let the computer do all of the work.
Perhaps the most compelling advantage of a DCT is improved fuel economy. Because power flow from the engine to the transmission is not interrupted, fuel efficiency increases dramatically. Some experts say that a six-speed DCT can deliver up to a 10 percent increase in relative fuel efficiency when compared to a conventional five-speed automatic.
Many car manufacturers are interested in DCT technology. However, some automakers are wary of the additional costs associated with modifying production lines to accommodate a new type of transmission. This could initially drive up the costs of cars outfitted with DCTs, which might discourage cost-conscious consumers.
In addition, manufacturers are already investing heavily in alternate transmission technologies. One of the most notable is the continuously variable transmission, or CVT. A CVT is a type of automatic transmission that uses a moving pulley system and a belt or chain to infinitely adjust the gear ratio across a wide range. CVTs also reduce shift shock and increase fuel efficiency significantly. But CVTs can't handle the high torque demands of performance cars.
DCTs don't have such issues and are ideal for high-performance vehicles. In Europe, where manual transmissions are preferred because of their performance and fuel efficiency, some predict that DCTs will capture 25 percent of the market. Just one percent of cars produced in Western Europe will be fitted with a CVT by 2012.
Next, we'll look at the history of the DCT and see what the future holds.


Feel free to ask me anything else you wish.
I will answer without mystery as someone else is doing.
Cheers
Wanni

Wanni. What is the cost of your gearbox in £ or $ in the UK?
Thanks
Mike

MikeP said:

Wanni. What is the cost of your gearbox in £ or $ in the UK?
Thanks
Mike

Click to expand...

Which one???
T906H, T906S, T1257DCT or TFD506S ???

T1257DCT is only for OEM supplies in order the software development is the most important investment.

About the others, let us wait the end of the deal between GearFox Italia, GearFox UK and the US importer, for US.

If the (one) T906H is for Europe, the list price is 15.500 €uros
If the (one) T906S is for Europe, the list price is 16.500 €uros

Take those prices ONLY as an indication.

Volumes and orders covered by guarranties are making the real price. We are OEMs as a priority. And we do like to sell systems and not units.
If I would have to sell you a gearbox just like that, I won't.
The interfacement to the engine and the vehicle is extremely important. (clutch, flywheel, cooling system, bell housing, shifting mechanism, etc...etc...)
Example. If you buy the best HI-FI stereo unit with ordinary speakers, the sound quality will be at the speakers level.
I am used to check all the new installations and if they are not agreed by me, the supply is aborted.
I probably look complicate but I expect the best results from my units and out of that I can not leave the installation in opinionists hands.
I am not here to make easy money but to sell a system which will give to the owner the best emotions in driving this sophisticate unit.
That's why I am telling you to be represented by one of you for setting up the application. Once it is done, then order 20 or 30 units all the same in order to reach the best quotation.
Anyway, forget the supply of one unit just for fun. I have a reputation to keep high.
Regards
Wanni

FOX1 said:

Anyway, forget the supply of one unit just for fun. I have a reputation to keep high.
Regards
Wanni

Click to expand...

Looks like anyone who wants only one will have to wait til someone writes off a car and then buy the trans from the wreckers!:lol: Situation normal for most guys anyway

Cheers,

Russ Noble said:

Looks like anyone who wants only one will have to wait til someone writes off a car and then buy the trans from the wreckers!:lol: Situation normal for most guys anyway

Cheers,

Click to expand...

Or, if you want to open your eyes and watch a bit more forward,
that one guy or manufacturer or .....starts a propper development program in order then to be in a position to supply a reliable system ( flywheel, ckutch, release bearing, linkage and drive shafts ) tested, designed, and sold to everybody for an affordable cost to all of them who are looking for certitudes and not for adventures.
It is too easy to sell a unit just to make easy money and leave the client in the shit for not being able to install it properly in his vehicle.
Exactly the worse advertisement which I do not want, my friend.
I am still thinking as an OEM supplyer.
Ciao
Wanni

IanAnderson said:

Wanni

That gearbox looks very interesting - to an untrained accountants eye.

What is the reason for increasing the number of gears? Is it purely to give a lorer RPM at cruising or is it for some other technical reason?

I have heard that with the bigger RPM changes during gear change the syncro works harder but surely that is the syncros job. Unless this causes excessive wear or some other roblem.

As I say it all interests me but I am far below your technical skill and ability.

Thanks
Ian.

Click to expand...

About why 7 speeds, I have already answered.
Let us go in the fine tuning of a gearbox, because you reached the point with the synchros questions.
Generally the synchros best operation is always a compromise for the development engineers.
As you can understand, you can build a confortable gearbox at medium revs ( which is usually the target ) accepting the fact it is miss used at high revs.
Why??? always because the target is to neet the 50% driver requirements, who is principally using the vehicle accordingly to the street regulations with some exceptions regarding sporadic sportly tries.
Normally an engine is reving 7.000 revs and up or down shifting at 2.500 is a bit out of routine. If I set up the best shifting for this range of revs, I can forget to engage any gear at 7.000, for exception by by passing the synchros. if I set up the best at 7.000 ten i will be in trouble at low revs to unlock the rings for the final ingagement, after the synchronisation point, for excess of power.
If you are used to drive constantly in a sportly mode, you shall contact a center where experts can customise the synchronisation to your personal needs.
I would build the activator springs much harder in order to keep synchronising but also I would increse the oil cooling for the rings in order to do not burn everything.
By removing the clutch damper I would reduce the clutch disk inertia and I would use a specific hi quality lubricant.
A small investement for the sportly driving pleasure.
Cheers
Wanni

Wanni

Many thanks for the explanation
I'm sorry but it will take me a lot of time to understand these things but eally find it all intresting.

But then again number crunching I find extremely easy!

Thanks again
Ian

It is a èleasure to explaine to interested persons how it works.
Pls feel free to ask as much as you need.

Now THIS is the gearbox I've been waiting for. Finally a box that I won’t blow apart. I will get my hands on one, as its for OEM and that’s exactly what I intend.

So far this sounds like the exact box I've been looking for. Able to handle my V8 torque, 7 speed, syncro, sequential, AND my fav, duel clutch!

Nothing but the best for my baby

How far away is this from production?

neongtsr said:

Now THIS is the gearbox I've been waiting for. Finally a box that I won’t blow apart. I will get my hands on one, as its for OEM and that’s exactly what I intend.

So far this sounds like the exact box I've been looking for. Able to handle my V8 torque, 7 speed, syncro, sequential, AND my fav, duel clutch!

Nothing but the best for my baby

How far away is this from production?

Click to expand...

Dear friend,
to be honest, this unit has been made for the development of the single rail shifter,the dual clutch developement and the basic software definition.
By visiting my web...default... sowhere you will find a picture with this unit cuted from solid next to me.
It is already in a vehicle , but only for those above mentioned developments.
Of course if someone wants a few, the production can easly start.
This unit is too long and it will be the cause of rear crash test failure.
The need of this lay out was just for not having the mechanics to be developed before.
This unit is a laboratory.
By putting it on 3 shafts wit the clutch behind the gearbox, then it become a suitable solution.
Thanks for your simpaty for my design.
Regards
Wanni