Stripped F1 Gearbox

All that has to do with the power train, gearbox, clutch, fuels and lubricants, etc. Generally the mechanical side of Formula One.
autogyro
autogyro
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Joined: 04 Oct 2009, 15:03

Re: Stripped F1 Gearbox

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strad wrote:they both allow you to be in two gears at one time
This is not possible as has been discused at length on this forum before.
Zero shift is a marketing hype not reality in engineering.
A stepped ratio gearbox remains that a range of gears with 'steps' between them.
Modern F1 gearboxes change gear very fast but they still 'change' gear.

It is possible to engage a gear to a shaft (partialy engage)at the same time as another gear is tranfering torque from the power source to the driving wheels.
It most certainly is NOT possible to fully 'engage' two gears at once.

F1 gearboxes of today as well as all layshaft gearboxes including 'twin clutch' and 'twin layshaft'types are exactly the same concept as the first motor vehicles of the 19th century.
IMO they have been obsolete for over 100 years even F1 gearboxes.

Cogs
Cogs
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Joined: 05 Nov 2010, 12:18

Re: Stripped F1 Gearbox

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Engaging 2 gears at once as well as driving torque (if only for a few ms) through 2 gears at once is possible and does happen.

As the new gear engages the previously driven gear is released. If we slow this event down for discussion purposes then at the instant the new gear engages torque is increasing at the point of contact and at the same time torque is decreasing from the contact of the previously driven gear. In effect within the stiffness of the material driving torque through both gears at the same time.

The dual barrel system which is set up so that dog rings are not engaged in sequential gear pairs are used to make sure that as the input shaft speed rapidly decelerates (for an up-shift) the previously driven dog ring is removed before going through backlash and causing a double engagement.

The trick is to manage the synchronisation energy. I assume that in F1 this is achieved by timed management of input torque by retarding the engine at exactly the same instant as the synchronisation of the inertia occurs. This will require a complex control strategy and the ability to monitor dog positions. In other applications the clutch can be modulated to equal engine torque thus isolating engine inertia from the synchronisation. Chemical energy can then be removed and enigne synchronised back to input shaft speed while maintaining constant input torque.

autogyro
autogyro
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Joined: 04 Oct 2009, 15:03

Re: Stripped F1 Gearbox

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Cogs wrote:Engaging 2 gears at once as well as driving torque (if only for a few ms) through 2 gears at once is possible and does happen.

As the new gear engages the previously driven gear is released. If we slow this event down for discussion purposes then at the instant the new gear engages torque is increasing at the point of contact and at the same time torque is decreasing from the contact of the previously driven gear. In effect within the stiffness of the material driving torque through both gears at the same time.

The dual barrel system which is set up so that dog rings are not engaged in sequential gear pairs are used to make sure that as the input shaft speed rapidly decelerates (for an up-shift) the previously driven dog ring is removed before going through backlash and causing a double engagement.

The trick is to manage the synchronisation energy. I assume that in F1 this is achieved by timed management of input torque by retarding the engine at exactly the same instant as the synchronisation of the inertia occurs. This will require a complex control strategy and the ability to monitor dog positions. In other applications the clutch can be modulated to equal engine torque thus isolating engine inertia from the synchronisation. Chemical energy can then be removed and enigne synchronised back to input shaft speed while maintaining constant input torque.
I am more than aware of the way gearchanges occur in F1 gearboxes.
The change can occur between the contact of two teeth in one gearset and contact between two teeth in another set, it can be that fast and I have designed gear sets to achieve this.
There are various types of engagement design that can be used ranging from ordinary dog clutches to ramps with balls, pins, ratchets, sprags. plates, springs and many others. Non of them can transmit the full available torque from the power source to the driven wheels using two gears engaged at the same time.
Just because there are a lot of clever nerds able to program computer control systems to the nth degree this will not change the fact that NO stepped box can drive in two ratios at the same time.
I am sick of all the nerd BS that continues to delude people into believing this.
All they are doing is finely controlling ancient 19th century mechanics, so no big deal.

hardingfv32
hardingfv32
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Joined: 03 Apr 2011, 19:42

Re: Stripped F1 Gearbox

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Any idea how the Weismann "ID Quickshift" gear cluster is supported AND engaged internally?

Brian

Cogs
Cogs
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Joined: 05 Nov 2010, 12:18

Re: Stripped F1 Gearbox

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I am more than aware of the way gearchanges occur in F1 gearboxes
Obviously not.
Non of them can transmit the full available torque from the power source to the driven wheels using two gears engaged at the same time.
Where have I suggested this?

The transfer of torque from gear A to gear B is not digital because the contact is not infinitely stiff. As the dogs are not infinitely stiff there has to be a time (only a few milliseconds) where the torque applied to gear A is reducing and the torque applied to gear B is increasing. So both gears are engaged at the same time (again only for a few milliseconds) and contributing to output torque.

The fact that NO stepped box can continuously drive two ratios at the same time is the exact reason why the previously driven gear (gear A) becomes released when gear B has full torque. Gear B has synchronised itself to the output shaft and because of constant mesh has also decelerated Gear A away from the dog ring......simple

I am not delusional....this is not theory because as you say the mechanics have existed for a very long time.

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strad
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Joined: 02 Jan 2010, 01:57

Re: Stripped F1 Gearbox

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Both gears are not driving at the same time...I think it was Ferrari that was almost like two gear boxes in one and had separate shafts and was basically in two gears at once...One was for odd numbered gears and one for even numbered gears.
And the way they all shift these days is to turn off the engine for a few Milliseconds while the shift takes place.
To achieve anything, you must be prepared to dabble on the boundary of disaster.”
Sir Stirling Moss

hardingfv32
hardingfv32
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Joined: 03 Apr 2011, 19:42

Re: Stripped F1 Gearbox

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Cogs wrote:there has to be a time (only a few milliseconds) where the torque applied to gear A is reducing and the torque applied to gear B is increasing. So both gears are engaged at the same time
This is not the case in all the road racing gear boxes that we are aware of. The cogged slider that is used to engaging the individual gears is not wide enough to be in contact with two gears at once.

Unless you can demonstrate a design, you are wrong!

Brian

Cogs
Cogs
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Re: Stripped F1 Gearbox

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And the way they all shift these days is to turn off the engine for a few Milliseconds while the shift takes place.
As I said.
The trick is to manage the synchronisation energy. I assume that in F1 this is achieved by timed management of input torque by retarding the engine at exactly the same instant as the synchronisation of the inertia occurs.
Unless you can demonstrate a design, you are wrong!
As I said.
The dual barrel system which is set up so that dog rings are not engaged in sequential gear pairs
Take another look at the image at the start of this thread. The upper barrel moves the forks for even gear selection and the lower barrel odd gear selection. Thus not requiring "the cogged slider" to be "wide enough to be in contact with two gears at once."

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jenkF1
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Joined: 18 Sep 2009, 14:52

Re: Stripped F1 Gearbox

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Im sorry but I can only see one layshaft on this gearbox and I thought everyone runs dual-clutch boxes for the last few years? I am not very knowledgeable on gearboxes, but I do know there is an alternate system similar to dual clutch in principle but mechanically different. Is this what we are seeing here?
Image

hardingfv32
hardingfv32
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Joined: 03 Apr 2011, 19:42

Re: Stripped F1 Gearbox

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Cogs wrote: The upper barrel moves the forks for even gear selection and the lower barrel odd gear selection. Thus not requiring "the cogged slider" to be "wide enough to be in contact with two gears at once."
Valid point. And I assume we never have neutral between gears, so that is not an issue.

I would then question the significance of this overlap. Starting with 100% torque in one gear and then transferring to 100% torque in another, does the torque from the 'combined' gears (sum) remain 100% during the transition.

Brian

Cogs
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Joined: 05 Nov 2010, 12:18

Re: Stripped F1 Gearbox

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hardingfv32 wrote:Starting with 100% torque in one gear and then transferring to 100% torque in another, does the torque from the 'combined' gears (sum) remain 100% during the transition.
A difficult answer.....

Prior to the shift the torque being applied to the first gear is equal to engine torque (assuming clutch capacity is greater) times the ratio at the output. During contact the torque seen at the new gear increases from zero to the sum of the engine torque times the ratio of the new gear but in addition there is a positive torque spike seen as the result of synchronisation of the engine inertia.

In reality what you will see is an increase in output torque during the time of torque transfer but yes in its raw form 100% of the torque present on the input side will be continuously delivered during the transition.
Last edited by Cogs on 09 Feb 2012, 00:44, edited 1 time in total.

Cogs
Cogs
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Joined: 05 Nov 2010, 12:18

Re: Stripped F1 Gearbox

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jenkF1 wrote:I thought everyone runs dual-clutch boxes for the last few years?
As far as I'm aware dual-clutch transmissions are banned.
jenkF1 wrote:I do know there is an alternate system similar to dual clutch in principle but mechanically different
Can you describe the alternate system?

hardingfv32
hardingfv32
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Joined: 03 Apr 2011, 19:42

Re: Stripped F1 Gearbox

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1) I see nothing in the current rules preventing dual clutch systems.

2) What is de-bounce?

9.8.3 Any de‐bounce time used to condition driver gear change requests must be fixed.

3) What is this about?

9.8.3 The minimum possible gear the driver is able to select must remain fixed whilst the car is moving.

Robbobnob
Robbobnob
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Joined: 21 May 2010, 04:03
Location: Auckland, New Zealand

Re: Stripped F1 Gearbox

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IIRC dual clutch systems aren't banned, but as they donot provide sufficient benefit for the increased weight and packaging constraints, formula 1 teams use a conventional single clutch system
"I continuously go further and further learning about my own limitations, my body limitations, psychological limitations. It's a way of life for me." - Ayrton Senna

autogyro
autogyro
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Joined: 04 Oct 2009, 15:03

Re: Stripped F1 Gearbox

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Tum te tum.

If there is a torque spike, then 100 percent torque is NOT being transmitted during the shift.
Would you explain the version of Newtonian Physics you are basing this 'constant' torque transfer gearshift illusion on?
It is not of this world.