Seamless Gearboxes Find The Gap

[autogyro]

http://www.youtube.com/watch?v=UL5h-m8x_hM

http://www.youtube.com/watch?v=IEcTIQQj ... re=related

I have a question

In the first video,the gears are labelled.
It distinctly shows 1st gear being engaged by the mechanism.

Question: Why then are the gears turning when the vehicle is stationary in neutral?

The mechanism shown in the second video is called a 'seamless' shift mechanism.
The operation relies basicaly on the high gear engaging the hub on the output shaft shown, by moving the slider and dogs assembly into mesh with the gear, using a sprung loaded selector fork (not shown)and locking the action with the other gear's slider ring.

The shift to the next higher gear is achieved by moving its slider ring and dogs assembly away from its locking position against the lower gear using its sprung loaded selector fork (not shown) and moving it along the hub into engagement with the high gear. The low gear slider ring then locks off the engagement.

As soon as the high gear slider ring moves away from the lower gear, the lower gear slider ring and bullets are only held in engagement by the input 'drive' torque applied to the gears. The lower gear's selector fork (not shown) is sprung loaded and if the fork (not shown) is moved to the disengage positon the lower gear sliper ring and dogs will disengage but only when the 'drive' torque holding the dogs in place is removed.

It has been continualy stated by experts that this only occurs when the higher gear engages with its slip ring dogs and it is the application of 'drive' torque to the hub through the dogs that releases 'drive' torque from the lower gear slip ring dogs, allowing the low gear's spring in its selector fork (not shown) to spring the low gear slip ring dogs out of engagement.

I hope any reader of this will carefully study the videos.
I am saying that ANY reduction in torque from the input to the geartrain will result in the lower gear slip ring dogs springing out of engagement with the lower gear, not just high gear engagement.
This can easily happen before the higher gear engages and it creates a GAP in torque transfer.

In all the graphs I have seen on this type of mechanism there have been a range of torque modulation methods to achieve this reduction of input torque.
When the lower gear disenages it ia a result of how much torque reduction is applied to input and the sprung loaded selector forks (not shown) timing.
Without torque modulation the shift would be like a sledge hammer.

These gearbox shift systems may be smooth at the expense of torque transfer efficiency but they are NOT 'seamless', other than in marketing terms.

I am not part of any marketing or promotional oraganisation connected in any way to manufacturers of these systems.
I welcome any qualified comments that contradict my conclusions.

I hope that this post is not seen as an attempt to do anything other than find out the facts on how these systems work.

[strad]

All I know is...I was right.

[Billzilla]

There is a slight wobble in the torque but there certainly is no gap in the torque transfer.

You went through ad-infinitum on that other forum and got your self banned for it. Don't go through the same thing here.

[f1aussie]

Can I ask some dumb questions???
Apologies if this has been raised before...
Why do we "allow" seamless shift transmissions???
Why not make the drivers "drive" by manually changing gear???
Or is this not technical enough for F1???
Surely this would ad to the "show" without the artifical elements of DRS???
I say make the drivers DRIVE and have to change gear!

[strad]

To put it simply..They can't. We would have to take a giant step backwards in a bunch of other areas affecting performance as well.

[f1aussie]

Would it be a "step backwards"???
It could be a step forwards!!!

[autogyro]

Would it be a "step backwards"???
It could be a step forwards!!!

Depends on how much you believe downforce aerodynamics is a step forward.
It certainly has little if any relevence to road vehicles.
F1 is supposed to be the pinnacle of vehicle technology, not just a real world version of computer gameing and a platform for huge investment in upside down model aeroplanes.

I HOPE that those reading this thread will carefully read my first post.
The explanation on how this so called 'seamless' mechanism works and how any reduction in input torque WILL disengage the lower gear before the higher gear applies.

I still await ANY qualified poster who can explain the operation of the mechanism in such a way as to contradict my statement that this is NOT either a 'zeroshift' or a 'seamless' gear shift mechanism.

I do not wiah to derail this thread or forum and only want technical responses.
I was unfairly banned by vested interest from posting in another forum and I will not repond to childish or arrogant posts.

[autogyro]

There is a slight wobble in the torque but there certainly is no gap in the torque transfer.

You went through ad-infinitum on that other forum and got your self banned for it. Don't go through the same thing here.

Please explain this 'slight wobble in torque'?

[autogyro]

I should like to ask a very simple technical question.
I should like to request an answer from anyone directly involved with these 'seamless' shift mechanisms.
I should like to request an explanation for the answer.

Question:-

Can the lower gear drive ring and dog assembly be disengaged from the lower gear
before the higher gear is engaged by reducing input torque to the geartrain?

[Jersey Tom]

Can I ask some dumb questions???
Apologies if this has been raised before...
Why do we "allow" seamless shift transmissions???
Why not make the drivers "drive" by manually changing gear???
Or is this not technical enough for F1???
Surely this would ad to the "show" without the artifical elements of DRS???

I could make the argument that forcing drivers to use a H-gate shifter or whatever is an artificiality in itself.

As for the original question in the post.. that description has a lot of "not shown" 's in it. Personally I'm more of a visual guy for grasping things. Would have to see the thing drawn out a bit better to get a better feel for what we're speaking of.

[thisisatest]

i could be wrong, but as ive seen the "zeroshift" laid out, it does require some positive torque when engaging the next harder gear, which then disengages the easier gear. i do not believe easing the torque will disengage the easier gear before actually engaging the harder gear, due to the back-cut in the... i forget the nomenclature, but it keeps the thing stuck in the gear. i believe the torque has to be interrupted to zero to actually disengage the drive early.

[autogyro]

i could be wrong, but as ive seen the "zeroshift" laid out, it does require some positive torque when engaging the next harder gear, which then disengages the easier gear. i do not believe easing the torque will disengage the easier gear before actually engaging the harder gear, due to the back-cut in the... i forget the nomenclature, but it keeps the thing stuck in the gear. i believe the torque has to be interrupted to zero to actually disengage the drive early.

The positive torque that is applied to the higher gear (shown in the video where no drive torque or torque control is present), does REDUCE the torque applied to the 'driving' lower gear.
This does (in the unloaded video), result in the sprung loaded selector fork for the lower gear,springing the lower gear dog ring out of engagement.

If this was attempted in the vehicle with drive load applied to a working drive train, it will result in a sledge hammer bang.

As explained and endlessly confirmed by those involved with the mechanism. Applying torque to the higher gear will reduce torque to the lower gear.
What I am stateing, is that REDUCING torque to the lower gear causes the disengagement, not the application of torque to the higher gear.
Therefore, if sufficient control over the engine torque and the main clutch is used, it is obviously possible to disengage the lower gear with NO NEED to apply torque to the high gear.

Look again at the 'cut out' you mention.
It is not there to 'retain' the dog ring component (the other dog ring does this), it is a ramp to help disengage the gear.
It is the spring on the selector fork (not shown) that has to overcome the engagement pressure on the gear, at anytime after the other selector ring is withdrawn from its locked position.
The time gap here, gives plenty of time for the low gear to disengage before the higher gear engages.
It depends on component timing and the amount of torque applied to the lower gear.

[autogyro]

Can I ask some dumb questions???
Apologies if this has been raised before...
Why do we "allow" seamless shift transmissions???
Why not make the drivers "drive" by manually changing gear???
Or is this not technical enough for F1???
Surely this would ad to the "show" without the artifical elements of DRS???

I could make the argument that forcing drivers to use a H-gate shifter or whatever is an artificiality in itself.

As for the original question in the post.. that description has a lot of "not shown" 's in it. Personally I'm more of a visual guy for grasping things. Would have to see the thing drawn out a bit better to get a better feel for what we're speaking of.

If as I believe, the current 'seamless' shift selectors extend the time that full torque 'flow' cannot occur during the gear shift (not just the shift overlap), then the old manual dog operated gearboxes that required NO torque modulation on upshifts simply driver skill, would appear to be more efficient in transfering torque.
This would be an efficiency issue not one of artificiality.
Perhaps a second a lap.
The H pattern is not the issue.

I agree that data available on these shift mechanisms conveniently leaves out at least half of the assential parts and most of the control data.
The forks that operate the selector ring/dog assemblies are sprung loaded for a start.
This is essential as the springs on the forks are the actuating component that disengages the gears.
Without showing these other mechanisms, those on one dimensional thinking have no chance of developing their thinking dynamicaly and they accept the basic promotional info.

[woody3says]

I will repeat my questions to you then:

You claim that a manual stick/clutch/foot combo is more efficient than a 40ms current F1 box? Would you agree that teams use the (when rules allow) systems and technologies that are the best to reach the goal of the fastest chassis possible? If a quickshift/zeroshift box is the slower torque transferring and lest efficient of the two, then why don't the teams use a manual dog box???

Speed rules.....if a manual were faster the teams would run those boxes. I give you the benefit of the doubt as much as I can, but your beef seems to be hostility due to your own box.

[thisisatest]

i believe his argument is specific in that seamless shift systems are not truly seamless.