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Seamless Gearboxes


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#151 carlt

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Posted 27 February 2012 - 14:35

for a better readable version of the graphic - torque goes to zero or not
http://www.zeroshift.com/68.html



Thanks

Maths has never been my forte [ anyone for te' definitely ]

Unless they are lying and cooking their graph - I see no 'Seam'

?

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#152 carlt

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Posted 27 February 2012 - 14:39

Am I correct in thinking that this is all controlled electronically ?

#153 TC3000

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Posted 27 February 2012 - 14:52

This has GOT to happen before the higher gear is FULLY engaged, otherwise you would be trying to put max torque through two gear sets rotating at different speeds.


yes, but you have a "window of opportunity" to retract the dog ring/bullets or whatever from the lower gear.
if you do so, before they get hit by the next dog from the gear, you don't have an issue.

in the moment the higher gear engages and takes the full torque, it will "overrun" the lower gear, the dogring will unload automaticly.
The "trick" is, to retract the dogring from the lower gear quick enough, before it get hit, by the next dog on the gear.

Depending on the number of dogs used, let's for the sake of this example say 4, you have a window of app. 75 deg, shaft rotation, where you can have two gears
"engaged" at the same time, with the higher one driving the output shaft, and still no disaster. The disaster will onlz happen,when the dogring of the lower gear is still
there to get hit by the next dog on the gear.

The delta rpm between the two gears, together with the "size of the window (75-100deg)" will get you the time, which you have to get the dogring of the lower gear "out of harms way".
That's pretty much how they operate a F1 gearbox these days, and why you have two shift barrels.

Edited by TC3000, 27 February 2012 - 15:01.


#154 24gerrard

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Posted 27 February 2012 - 16:35

yes, but you have a "window of opportunity" to retract the dog ring/bullets or whatever from the lower gear.
if you do so, before they get hit by the next dog from the gear, you don't have an issue.

in the moment the higher gear engages and takes the full torque, it will "overrun" the lower gear, the dogring will unload automaticly.
The "trick" is, to retract the dogring from the lower gear quick enough, before it get hit, by the next dog on the gear.

Depending on the number of dogs used, let's for the sake of this example say 4, you have a window of app. 75 deg, shaft rotation, where you can have two gears
"engaged" at the same time, with the higher one driving the output shaft, and still no disaster. The disaster will onlz happen,when the dogring of the lower gear is still
there to get hit by the next dog on the gear.

The delta rpm between the two gears, together with the "size of the window (75-100deg)" will get you the time, which you have to get the dogring of the lower gear "out of harms way".
That's pretty much how they operate a F1 gearbox these days, and why you have two shift barrels.


'Window of opertunity' = gap
As you explain you CANNOT transfer torque with both gears fully engaged, therefore the next higher gear CANNOT be FULLY engaged until the lower is disengaged.
And the other way round. The lower gear cannot be engaged if the next higher gear is FULLY engaged.

#155 24gerrard

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Posted 27 February 2012 - 16:37

Thanks

Maths has never been my forte [ anyone for te' definitely ]

Unless they are lying and cooking their graph - I see no 'Seam'

?


Take a good hard look at the graph.

#156 NTSOS

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Posted 27 February 2012 - 17:22

Take a good hard look at the graph.



I must be blind, but where exactly in the graph indicates *zero torque flow* between 1st and 2nd gear shifts?

Posted Image

John

Edited by NTSOS, 27 February 2012 - 19:29.


#157 Tony Matthews

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Posted 27 February 2012 - 17:48

Surely, on any other thread, on any other forum, this would be classed as trolling. Good thing I don't read most of it...

#158 TC3000

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Posted 27 February 2012 - 18:02

'Window of opertunity' = gap
As you explain you CANNOT transfer torque with both gears fully engaged, therefore the next higher gear CANNOT be FULLY engaged until the lower is disengaged.
And the other way round. The lower gear cannot be engaged if the next higher gear is FULLY engaged.


I did not explain this - - it´s just what you choose to make out of it.
Your way of thinking centers around a classical dog ring design, where you would need to disengage the lower gear first, in order to engage the higher gear.
But this is not a prerequisite if you either use two shift barrels/rails or a split dog ring design, as in the zeroshift case.
In this case you just engage the next higher gear, as as soon as you do so, it over-runs the lower gear, unloading the dogs in the process.
There is no need to reduce torque to disengage the lower gear first.

Ask Mat´s Norway for an illustrations of any RC-Car two speed gearbox, which uses a freewheel mechanism in the lower gear, as soon as the higher gear engages, via a centrifugal clutch in this case,
it just takes over the running/drive of the output shaft, and the lower gear freewheels on the hub.
No need to reduce any torque whatsoever to disengage the lower gear first.

#159 MatsNorway

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Posted 27 February 2012 - 18:45

I think understand how some of how that Zeroshift works now. the Chamfer added on the arms makes the lower gear disengage when the faster moving gear connects.

To put it simply.. there is a microscopic gap during upshift and a more normal one.. probably.. during downshift.

The graph displayed is useless in this sense.. its far too crude.

This Zeroshift does not need to lift on upshift and hence it should be named zerolift.

A rime!



btw. whats the reason for having a splitt gear and ring?


Edit: oohh it can slipp on the gear too.

Edited by MatsNorway, 27 February 2012 - 19:04.


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#160 jpf

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Posted 27 February 2012 - 20:07

Surely, on any other thread, on any other forum, this would be classed as trolling. Good thing I don't read most of it...


Presumably, he is writing all of this from prison, having burnt to the ground the headquarters of every company which makes "wrinkle free" pants.

#161 Tony Matthews

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Posted 27 February 2012 - 20:43

To put it simply.. there is a microscopic gap during upshift and a more normal one.. probably.. during downshift.

To put ot even more simply - there is no gap.

#162 carlt

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Posted 27 February 2012 - 20:46

To put ot even more simply - there is no gap.


is that another of your famous aphorisumsis ?

#163 Tony Matthews

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Posted 27 February 2012 - 20:54

If I find anyone meditating on it they'll hear from my solicitor, toot sweet.

#164 gruntguru

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Posted 27 February 2012 - 21:51

If you waited this long to disengage the lower gear, you would have a lock up or bind up followed by broken bits in the gear case.

How long is "this long". The entire shift takes 50ms and I would estimate the time during which both gears are driving and an "elastic handover" is occuring, takes only a small fraction of that. These components are "elastic" no matter how rigid they might seem.

The handbag is actually a good analogy. Lets say the handbag is heavy and the little old lady is dragging it by the strap along the pavement at say 1 m/s and this requires a pulling force of 100N. A mugger approaches from behind at 2 m/s and grabs the strap as he passes. The handbag accelerates up to 2m/s and the force in the strap spikes breifly to 150N due to inertia of the handbag, before settling back to 100N. Just prior to this "force spike" there is a period where both the lady and the mugger are sharing the effort. This sharing starts at 100% lady and 0% mugger, but transitions smoothly to 0% and 100% respectively - eg at some point in the middle of the handover the ratio will be 50:50 however, at no point does the force in the strap drop to zero.

The zeroshift shift is similar to the ratchet style shift, where the higher gear is engaged while the lower is still driving. A (very brief) handover period occurs while the new gear takes the strain and the lower gear continues to drive (at a steadily diminishing level) during the entire handover.

#165 24gerrard

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Posted 27 February 2012 - 22:09

Hahaha and there I was thinking you clever guys could read a graph.

Take a good hard look.
The gear shift on the graph shown takes one twentieth of a second.
Which accounts for you guys being unable to see the drop to zero torque on the output.
BECAUSE THE ACTUAL SHIFT TAKES 50 MS.
I wont repeat Tonys comment. (NSBACS)
Clever these marketing guys aint they.

And no I wont get bogged down here with the math, I pay people to do that for me, just like I pay people to draw Tony.

Edited by 24gerrard, 27 February 2012 - 22:09.


#166 24gerrard

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Posted 27 February 2012 - 22:12

Presumably, he is writing all of this from prison, having burnt to the ground the headquarters of every company which makes "wrinkle free" pants.


Dont need to they do it for themselves.

#167 24gerrard

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Posted 27 February 2012 - 22:21

I did not explain this - - it´s just what you choose to make out of it.
Your way of thinking centers around a classical dog ring design, where you would need to disengage the lower gear first, in order to engage the higher gear.
But this is not a prerequisite if you either use two shift barrels/rails or a split dog ring design, as in the zeroshift case.
In this case you just engage the next higher gear, as as soon as you do so, it over-runs the lower gear, unloading the dogs in the process.
There is no need to reduce torque to disengage the lower gear first.

Ask Mat´s Norway for an illustrations of any RC-Car two speed gearbox, which uses a freewheel mechanism in the lower gear, as soon as the higher gear engages, via a centrifugal clutch in this case,
it just takes over the running/drive of the output shaft, and the lower gear freewheels on the hub.
No need to reduce any torque whatsoever to disengage the lower gear first.


In this case you just engage the next higher gear, as as soon as you do so, it over-runs the lower gear,

This would mean you are saying the lower gear is fully engaged at the same time as the next higher gear.
This is impossible.

#168 carlt

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Posted 27 February 2012 - 22:30

The handbag is actually a good analogy. Lets say the handbag is heavy and the little old lady is dragging it by the strap along the pavement



you've spoilt it now

I was imagining Cheapy had the bag of wonga

#169 24gerrard

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Posted 27 February 2012 - 22:30

How long is "this long". The entire shift takes 50ms and I would estimate the time during which both gears are driving and an "elastic handover" is occuring, takes only a small fraction of that. These components are "elastic" no matter how rigid they might seem.

The handbag is actually a good analogy. Lets say the handbag is heavy and the little old lady is dragging it by the strap along the pavement at say 1 m/s and this requires a pulling force of 100N. A mugger approaches from behind at 2 m/s and grabs the strap as he passes. The handbag accelerates up to 2m/s and the force in the strap spikes breifly to 150N due to inertia of the handbag, before settling back to 100N. Just prior to this "force spike" there is a period where both the lady and the mugger are sharing the effort. This sharing starts at 100% lady and 0% mugger, but transitions smoothly to 0% and 100% respectively - eg at some point in the middle of the handover the ratio will be 50:50 however, at no point does the force in the strap drop to zero.

The zeroshift shift is similar to the ratchet style shift, where the higher gear is engaged while the lower is still driving. A (very brief) handover period occurs while the new gear takes the strain and the lower gear continues to drive (at a steadily diminishing level) during the entire handover.


Damn grunt, now we have an elastic handover.
Is this some kind of contraceptive engagement?
I thought that was where some draughtsmen got their contracts.

#170 TC3000

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Posted 27 February 2012 - 22:35

This would mean you are saying the lower gear is fully engaged at the same time as the next higher gear.
This is impossible.


Impossible is just a big word thrown around by small men who find it easier to live in the world they’ve been given than to explore the power they have to change it.
Impossible is not a fact. It’s an opinion.


I will leave you have your opinion, I guess that´s all what you will ever put forward in this forum.
If you have some hard data, graphs, calculations and/or test results to back up some of your claims, get back to me.

So long - have a nice evening, and enjoy watching your veggies growth.

Edited by TC3000, 27 February 2012 - 22:36.


#171 24gerrard

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Posted 27 February 2012 - 22:43

I will leave you have your opinion, I guess that´s all what you will ever put forward in this forum.
If you have some hard data, graphs, calculations and/or test results to back up some of your claims, get back to me.

So long - have a nice evening, and enjoy watching your veggies growth.


Have a nice time using those 19th century layshaft gearboxes.
Must be hell wasting all that energy.
You will have to explain to me one day how you trick physics and engage two gears at the same time.
Impossible is an adjective, it is neither fact or opinion.
It can be a challenge for those with sufficient lack of self opinion to meet it.

Edited by 24gerrard, 27 February 2012 - 22:49.


#172 Wuzak

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Posted 27 February 2012 - 23:43

Hahaha and there I was thinking you clever guys could read a graph.

Take a good hard look.
The gear shift on the graph shown takes one twentieth of a second.
Which accounts for you guys being unable to see the drop to zero torque on the output.
BECAUSE THE ACTUAL SHIFT TAKES 50 MS.
I wont repeat Tonys comment. (NSBACS)
Clever these marketing guys aint they.

And no I wont get bogged down here with the math, I pay people to do that for me, just like I pay people to draw Tony.



Perhaps you could highlight on the graph where the output torque falls to zero, and show how long that remains the case?

#173 carlt

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Posted 27 February 2012 - 23:52

You will have to explain to me one day how you trick physics and engage two gears at the same time.


with Grunts elastic contraceptive

#174 gruntguru

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Posted 28 February 2012 - 00:59

Damn grunt, now we have an elastic handover.
Is this some kind of contraceptive engagement?
I thought that was where some draughtsmen got their contracts.

If only you knew how foolish you appear - posing as an engineer on this forum while remaining totally ignorant of basic engineering terminology.

#175 gruntguru

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Posted 28 February 2012 - 01:01

In this case you just engage the next higher gear, as as soon as you do so, it over-runs the lower gear,

This would mean you are saying the lower gear is fully engaged at the same time as the next higher gear.
This is impossible.

Totally possible if the lower gear has a freewheel/ratchet mechanism which is exactly what the zeroshift is.

#176 Engineguy

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Posted 28 February 2012 - 02:06

The Story of O

Truck "O" is heavily loaded, but its drivetrain has been removed, so truck 3 is pushing it down the road at truck 3's maximum speed of 30 mph.

Truck 3 is pushing from a position off to the right side because there is a chain from truck O to truck "S" following 3 lengths back... like truck O, truck S has its drivetrain removed.

Truck 4 comes along to the left of the train of trucks O, 3 and S. Truck 4 is going 38 mph. It scrubs along the side of truck S until it gets clear of it and swerves into the space between O and S. Truck 3 is still in his position, chuggin' along pushing, but truck 4 is also laterally in pushing position. Since truck 4 is going faster it immediately eats up the space and contacts the rear of truck O. Since 4 is going faster than 3, the load is removed from 3 at the same instant 4 touches O. At no point was truck O not being pushed... not a millisecond, not a nanosecond.

Now truck 3 is still laterally in position to the right of the O-to-S chain and truck 4 is laterally in position to the left of the chain. Thus they can be said to both be "engaged" but only 4 is in contact. Truck 3 is floating in its position momentarily, drifting from the front of the space toward the back.

Truck 4 got slowed to 34 mph when it took on the now 34 mph load, but that's faster than truck 3 wants to go, so it needs to swearve to the right before truck S starts pushing it. If it doesn't actively get out of the way in time, that's OK too... 'cause the end of 3's rear bumper is beveled... and there's a big V snowplow on the front of S (duh, that's why they call it truck S; for snowplow). It can nudge 3 over to the shoulder... when it does, there is a loud CLANK sound just like them F1 cars make when they shift gears.

Later, truck 4 has got O and S up to 38 mph now, but is approaching redline. Truck 3 has disappered in the rearview mirror... but wait! There is someone else catching up! It's truck 5 catching up going 45 mph in the right lane... and even further back is truck 6 in the left lane going 50 mph... and way further back is truck 7 in the right lane going 55 mph.

Unfortunately, even further back, there is a bright green car that says "Go Daddy" on the side. It's coming at 198 mph and we all know what's gonna happen. :eek:

Edited by Engineguy, 28 February 2012 - 02:09.


#177 Kelpiecross

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Posted 28 February 2012 - 02:53

If only you knew how foolish you appear - posing as an engineer on this forum while remaining totally ignorant of basic engineering terminology.


Probably no need to be insulting - there have been certain other people who have persistently pushed endlessly seemingly unlikely points of view - the subjects of GW and the BRV come to mind.

Perhaps 24G could describe his own gear system? Unless he all ready has of course.

#178 cheapracer

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Posted 28 February 2012 - 05:54

There has to be a gap in torque to allow the lower gear driving bullets to disengage.


No, the pawls simply have a ramp ground on their backface, the instant the higher gear is driving the speed difference of the lower gear merely pushes the pawl out of it's way when the next dog hits it.

There driving face has no pressure on it as it has lost contact because the higher gear engagement has decelerated the pawl.

For those who would like to know how it works;

1/ pawls are pushing blue dog (attached to/drives gear of course).

2/ dark red pawl moves over to catch/drive red dog, once engaged to red dog is driving 100%.

3/ while red dog is now turning at a slower speed (it always was), blue dog continues forward at higher rate leaving pawl behind and if pale blue pawl hasn't cleared yet next blur dog coming will assist it.

4/ fully engaged red dog blue dogs free to spin.

The secret to this system is that the pawls can work independently of each other although being on the same hub.

BTW, the hub drives the mainshaft, not the gears, they just produce the speed/ratio the hub is driven at.


Posted Image


The only reason there is any gap in torque or speed on the graph (that I didn't post) is from metal elasticity, lubricant dispersing, dog's undercut engaging and/or engineered in momentary torque drop to protect the gear train from the "slam" when dark red pawl hits red dog.

Edited by cheapracer, 28 February 2012 - 05:56.


#179 MatsNorway

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Posted 28 February 2012 - 06:56

I think everyone here would agree that the Zeroshift does not have both gears pushing the bike on the same time. When 2nd goes in, first gear slides out because of the ramping.



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#180 Catalina Park

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Posted 28 February 2012 - 07:30

Surely, on any other thread, on any other forum, this would be classed as trolling. Good thing I don't read most of it...

I was going to used this thread as a drinking game, every time you see the words "You have chosen to ignore all posts from:" you have a drink.
I think I need to reload the fridge.

#181 Tony Matthews

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Posted 28 February 2012 - 08:46

You'll be telling us next that the fridge can be refilled before it's completely empty. This is, of course, technicaly impossible.

#182 cheapracer

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Posted 28 February 2012 - 09:03

You'll be telling us next that the fridge can be refilled before it's completely empty. This is, of course, technicaly impossible.


Shit did I just laff hard!! :rotfl: :rotfl:


#183 carlt

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Posted 28 February 2012 - 09:08

1. Some of the bullets partialy engage on the high gear dog face and this overruns the lower gear, allowing it to disengage.
2. During the instant of disengagement no torque is transfered from input to output.
3. Torque from input is only enough to rotate the dog face on the higher gear with friction bullet contact to achieve this overrun until the bullets fully engage in the high gear dog.
4. As the bullets engage fully in the next higher gear there is a spike. This is because the lower gear is no longer engaged and the higher gear is engageing.
I do not care if the gap is half that in time as for the 'big bang', it is still a gap in torque transfer.

1 . "the higher gear overruns the the lower gear" it must be transmitting some torque ?
2. enough torque is transmitted through the higher gear to 'overrun' the lower gear Which causes the bullets to disengage from the lower gear
3. the bullets appear,in the diagrams, to be able to lock - more than just friction
4. the lower gear is disengaging AS the higher gear is engaging

On all the threads you post on you bang on about everyone else needing to move their thinking on into 21st century

maybe this is a reverse case in point

The blurb on the article you linked to is saying that with modern materials and electronic control their system CAN engage 2 gears at the same time

The normal "19th century" moment of impact [ when the box locks up or explodes] is so fast it can be ironed out with the elasticity of materials and electronically controlled clutching
[I think you said 50 ml sec for the change , this would be the length of time of Both gears are engaged and the elasticity/windup/clutching to take place ]

They state "A spike can be smoothed out , a hole[gap] cannot be filled "

Are you saying they are Lying ?

#184 cheapracer

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Posted 28 February 2012 - 09:15

When 2nd goes in, first gear slides out because of the ramping.


No, lower gear merely continues at it's speed and it's pawls are simply left behind because the hub is now travelling at the same speed as the higher gear - then the solenoid shuffles it sideways out of the way - the ramp is there as a safety backup/assist. You would have roughly 1/70th of a second at around 8000rpm for the pawl to clear a typical 1st to 2nd (3:1 to 2:1) change and more time for the upper gears (close ratio box has less speed difference between gears).


....... their system CAN engage 2 gears at the same time


Yes, both in the "engaged" position but one not driving, one has it's pawl(s) merely taking up the empty space between the dogs for a moment in time but is cleared before the next one arrives (or the next one will clear the pawl via the ramp).

Edited by cheapracer, 28 February 2012 - 09:24.


#185 24gerrard

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Posted 28 February 2012 - 09:23

I must be blind, but where exactly in the graph indicates *zero torque flow* between 1st and 2nd gear shifts?

Posted Image


Where to start?

The original dog ringed auto and semi auto shifting layshaft boxes could achieve from 30ms to 50ms.
The new so called 'seamless' layshaft boxes have not increased this shift speed.
The reason for these shift systems is therefore NOT to increase the shift speed.
It is to smooth the shifts and to reduce wear and damage to the components.

Back to the graph, I will simply ask if there is anyone out there who can put me right on the following points 2 of many.

The engine rpm trace?
It remains constant through the shift. How can it do this?

The input shaft rpm trace?
It correctly drops during the shift to a new level but it parts company with the engine rpm trace?
The only way it can do this is if the clutch disengages?

#186 cheapracer

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Posted 28 February 2012 - 09:31

The engine rpm trace?
It remains constant through the shift. How can it do this?


They put a n 18 year old "Ricer" driver in the car.



The only way it can do this is if the clutch disengages?


They state in the article they do this to unload the box for safety ie; "the slam" when the next gear engages - things would break in short time otherwise.

"By briefly reducing the clamping torque on the plates during the shift, it allows a moment’s slip that dissipates the unwanted energy......"

#187 24gerrard

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Posted 28 February 2012 - 09:44

So the shifts are UNLOADED then Cheapy I see.
The clutch 'slip' continues for four tenths of a second at least and off the graph, interesting.

Back to the graph.
Is this the graph of a lawn mower powertrain?
3250rpm dropping to below 3000rpm, should cut my grass OK.

Edited by 24gerrard, 28 February 2012 - 10:10.


#188 MatsNorway

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Posted 28 February 2012 - 10:10

No, lower gear merely continues at it's speed and it's pawls are simply left behind because the hub is now travelling at the same speed as the higher gear - then the solenoid shuffles it sideways out of the way - the ramp is there as a safety backup/assist. You would have roughly 1/70th of a second at around 8000rpm for the pawl to clear a typical 1st to 2nd (3:1 to 2:1) change and more time for the upper gears (close ratio box has less speed difference between gears).


Impressive then.

Yes, both in the "engaged" position but one not driving,


That means by definition that only one gear can be engaged at the same time.

Mechanics . (of gears or the like) to interlock.

Interlock
4. to lock one with another.

Lock
to join or unite firmly by interlinking or intertwining: to lock arms.

Can everyone agree upon that the gearbox does not have two gears going on the same time? it just shifts them impressivelly fast.

Cheapy or others why the pads on the gears? im fairly blank on gearboxes.

#189 24gerrard

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Posted 28 February 2012 - 10:16

They put a n 18 year old "Ricer" driver in the car.

They state in the article they do this to unload the box for safety ie; "the slam" when the next gear engages - things would break in short time otherwise.

"By briefly reducing the clamping torque on the plates during the shift, it allows a moment’s slip that dissipates the unwanted energy......"


You can do better than this Cheapy.
Engine rpm can only be kept that constant with a slipping clutch through a shift with, wait for it......electronics programmed to prevent engine run away. That means compromised power delivery and reduced lap times.

It is not a moments slip Cheapy the clutch slips for nearly four tenths of a second and then slips off the graph.
Add that up for a race distance and it is a whole lot of wasted fuel buddy.
Mind you I expect that with a gear concept from the 1890's.

The clutch slip is in fact essential for the shift to happen in these so called 'seamless' gearboxes, unlike a manual dog ring box or an early dog ring auto shift box, both of which could be shifted without clutch slip with racing gearshifts.
Very jerky, lots of wear and a high potential for breakage but non the less more efficient at toque tranfer and with the same shift speed.

Edited by 24gerrard, 28 February 2012 - 11:00.


#190 Catalina Park

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Posted 28 February 2012 - 10:42

You'll be telling us next that the fridge can be refilled before it's completely empty. This is, of course, technicaly impossible.

It might well be impossible but I will never know because the people that would tell me are all on the ignore list.

I better stop reading, I have had 18 drinks since opening this thread today.

#191 carlt

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Posted 28 February 2012 - 10:43

Mind you I expect that with a gear concept from the 1890's.


I suggest You start looking at the layshaft box with 21st Century thinking ?

#192 24gerrard

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Posted 28 February 2012 - 11:03

I suggest You start looking at the layshaft box with 21st Century thinking ?


Threw the layshaft concept out the window in 1976 carl.
I proved that epicyclic geartrains could be more efficient and stronger for less weight and size.


#193 Tony Matthews

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Posted 28 February 2012 - 11:27

Posted on: Oct 19 2010, 18:16




For Tony: Seamless upshift in F1 is achieved in one of two ways; twin barrels or over-run ratchets.



In the twin barrel system one barrel controls the odd numbered shift forks - 1 3 5 7 and the other the even 2 4 6 forks. To upshift from say 3rd to 4th the odd barrel rotates first to bring the 3rd gear fork out of engagement - the dog ring is held in engagement by the torque being applied through the gear so the fork becomes preloaded. The even barrel rotates to move the 4th gear fork and dog-ring into engagement and 4th gear starts to transmit torque - because it is a higher gear this unloads the torque from the lower gear and the preloaded fork flicks the dog ring out of engagement with third gear before the gear dogs hit the over-run side of the dog ring.



In the ratchet system each of the mainshaft gears has an assembly that allows the gears to spin freely in over-run on the shaft. For the same 3rd to 4th shift the 3rd gear is driving the mainshaft, the barrel rotates to move the 4th gear fork and engage the dog ring with 4th gear. 4th gear starts to transmit torque and the 3rd gear is allowed to over-run the shaft by the ratchet system. The barrel continues to rotate to disengage the 3rd gear fork and dog ring completing the shift. The ratchet is locked for downshifts so that the gear can drive the mainshaft in over-run.


From rachael - note the date - and if anyone has a problem reading this and understanding such eloquent technical writing, from someone who has, I suspect, more recent F1 gearbox experience than anyone else posting on this tedious thread, then there is an obvious inability to understand almost anything, or they are a troll...

I'm tired of looking at pages of ignored posts, so I'm outta here.

#194 ferruccio

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Posted 28 February 2012 - 11:57

Posted on: Oct 19 2010, 18:16




For Tony: Seamless upshift in F1 is achieved in one of two ways; twin barrels or over-run ratchets.





From rachael - note the date - and if anyone has a problem reading this and understanding such eloquent technical writing, from someone who has, I suspect, more recent F1 gearbox experience than anyone else posting on this tedious thread, then there is an obvious inability to understand almost anything, or they are a troll...

I'm tired of looking at pages of ignored posts, so I'm outta here.


Waste of time Tony. The explanation will be deemed invalid because:
1. It is an 1890s design
2. The ECU smoothens the Torque. This is unacceptable, not Kosher.
3. It is not a 21st century epicyclic geartrain (presumably) by one clever person
4. Add as necessary

I've lost track of the point of this thread. I can only go back to the first post which presents an issue with semantics more than anything else - what is defined as 'seamless'.

I can have Mike Gascoyne or Mark Smith or Lewis Butler themselves or better still someone from RedBull Technologies explain the workings of the Caterham car and it's not going to make headway because they're not using someone's clever 21st century concept. The more interesting question would more likely be what is standing between this 'clever' concept and the rest of the automotive world? Judging by the way the arguments have been presented, I suspect the answer to this has to be the person behind the clever concept.


#195 cheapracer

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Posted 28 February 2012 - 12:27

Mechanics . (of gears or the like) to interlock.

Interlock
4. to lock one with another.


They are both interlocked momentarily, there just happens to be enough clearance that prevents binding before withdrawal.

I have no idea what you mean by "pads".


#196 24gerrard

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Posted 28 February 2012 - 13:25

They are both interlocked momentarily, there just happens to be enough clearance that prevents binding before withdrawal.

I have no idea what you mean by "pads".


Nope

#197 24gerrard

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Posted 28 February 2012 - 13:34

Waste of time Tony. The explanation will be deemed invalid because:
1. It is an 1890s design
2. The ECU smoothens the Torque. This is unacceptable, not Kosher.
3. It is not a 21st century epicyclic geartrain (presumably) by one clever person
4. Add as necessary

I've lost track of the point of this thread. I can only go back to the first post which presents an issue with semantics more than anything else - what is defined as 'seamless'.

I can have Mike Gascoyne or Mark Smith or Lewis Butler themselves or better still someone from RedBull Technologies explain the workings of the Caterham car and it's not going to make headway because they're not using someone's clever 21st century concept. The more interesting question would more likely be what is standing between this 'clever' concept and the rest of the automotive world? Judging by the way the arguments have been presented, I suspect the answer to this has to be the person behind the clever concept.


I look forward to Mike Gascoyne's comments, or any of the others you mention.
The barriers to any radicaly new vehicle engineering concepts in F1 other than aero are obvious.

The point of the thread was very simple, to prove that the terms 'seamless' and 'zeroshift' do not apply to any form of stepped layshaft gearbox.
It was not to decry the obvious engineering abilities and in some cases brilliance of those involved with these semi automatic gearbox shift systems.

The fact that the layshaft stepped gearbox concept is the same today as it was in the 1890's is my real beef.
Tarting it up will not stop it from being long out of date.

#198 cheapracer

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Posted 28 February 2012 - 13:45

They are both interlocked momentarily, there just happens to be enough clearance that prevents binding before withdrawal.


Nope



Every gear that drives another gear in the world is interlocked and they all have side clearances (lash), the Zeroshift happens to have a chunk of lash.

Refer drawing #2 for both interlocked and 3 for the lash for without that lash things would go "bang";

Posted Image

Have you noticed 24 that no-one agrees with you, and I mean not one single person including the manufacturers? - there is a time to fight and then there's a time to suck it up and pull your head in, you have reached the latter on this subject.

As with Tony, time to pull the pin on this one, I'm off to Cat-Park's house to check on the fridge theory ...

Edited by cheapracer, 28 February 2012 - 13:49.


#199 24gerrard

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Posted 28 February 2012 - 13:47

In the twin barrel system one barrel controls the odd numbered shift forks - 1 3 5 7 and the other the even 2 4 6 forks. To upshift from say 3rd to 4th the odd barrel rotates first to bring the 3rd gear fork out of engagement - the dog ring is held in engagement by the torque being applied through the gear so the fork becomes preloaded. The even barrel rotates to move the 4th gear fork and dog-ring into engagement and 4th gear starts to transmit torque - because it is a higher gear this unloads the torque from the lower gear and the preloaded fork flicks the dog ring out of engagement with third gear before the gear dogs hit the over-run side of the dog ring.

In the ratchet system each of the mainshaft gears has an assembly that allows the gears to spin freely in over-run on the shaft. For the same 3rd to 4th shift the 3rd gear is driving the mainshaft, the barrel rotates to move the 4th gear fork and engage the dog ring with 4th gear. 4th gear starts to transmit torque and the 3rd gear is allowed to over-run the shaft by the ratchet system. The barrel continues to rotate to disengage the 3rd gear fork and dog ring completing the shift. The ratchet is locked for downshifts so that the gear can drive the mainshaft in over-run.


Good explanation, I agree completely. Apart that is from the above.
I think you will find that in most designs the mainshaft drives the gear on over-run.
Two gears are not FULLY engaged at the same time. The ratchets or dog rings may be, that is not FULL gear engagement.
In fact it is some 70 to 110 degrees away from FULL engagement.
At the instant of change there is a gap, therefore the system cannot be 'seamless'.
If maximum engine torque can be transfered through the 30 to 50ms of the actual shift, then why does the clutch slip for approximately five tenths of a second and why does the engine management hold engine revs and torque output down?
If the graph shown had a wide enough range to show 30 to 50 ms it would show the gap.
These are 'constant mesh' gearboxes so please do not explain engaged as component contact alone, if this were the case under your definition the whole gearset would be engaged all at the same time, the gears are only fully engaged when they are transfering torque from input to output.

Edited by 24gerrard, 28 February 2012 - 14:21.


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#200 cheapracer

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Posted 28 February 2012 - 14:01

In fact it is some 70 to 110 degrees away from FULL engagement.


You just don't get it do you??

There is some 70 - 110 degrees for the lower gear to be disengaged after both gears are engaged before everything locks up.

There are people who read these and similar forums in a quest for knowledge, stop messing their minds up.