F1 Timing Gear Damper, a closer look

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Brian.G
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F1 Timing Gear Damper, a closer look

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Another part under the spot light, this time the Timing Gear Damper.

In this thread I will be unlocking a few secrets hidden within this part - The F1 Timing Gear Damper, mainly its construction, oiling, and some other features. It's from my own F1 V10 engine and is also used in the later V8 engine and one that had a 20,000rpm+ rev limit. There are two of these dampers used per engine - both driven off the crank gear - each one driving on up to the heads as shown on the V8 engine below,

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(Image Courtesy of Luke_Bywater - Google Search)



If you have not read the discussion about the Timing Gear Cover from the V8 since it features briefly in this discussion it can be viewed here > https://www.f1technical.net/forum/viewt ... =4&t=26358. The v10 and v8 damper gears and timing covers are same/similar in terms of design.

The need for the Timing Gear Damper showed its head very early on back in the DFV days. Crank torsional vibrations as well as resonance in the timing gear trains at particular rpms lead to many failed valve and gear trains on the DFV so a solution was required to smooth these vibrations within the gear train. In simple terms the job of the Timing Gear Damper is to smooth out resonance which if left unchecked can quickly become destructive. As the years went by, the problem didn't go away and because of this Timing Gear Train dampers can be found in all F1 Engines today - In fact, the Timing Gear Damper below has not changed much at all in terms of design and layout since Keith Duckworth's original solution back in the 70s on the DFV. Back then it had two names over the time, "Quill Hub Damper", and "Deflection Absorber".

So with that in mind, onto the part itself.

From the outside it doesn't look much,

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Oil drilling's visible around central bearing - the gear as a whole held captive axially by the Timing Gear Cover,

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The rear side, hub screws removed for disassembly,

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Rear cover removed you can see the detail of the Silicon Bronze axial thrust ring, because there is rotational movement of approx 1.3 degrees between the rear cover plate and the outer ring gear a bearing bronze is used here. It is held from spinning with notched pockets,

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A few close-ups of the inside of the main gear assembly, notice the small torsion bars which are the only parts transferring rotational movement from the center hub, to the outer ring gear,

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The small torsion bars are machined from one piece of steel and have small arms extending out to bushings in the outer ring gear,

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Although the torsion bars look to be two parts, the recess and holes are only there to accurately jig them for the torsion bar section(not shown) grinding operation. Like any torsion bar, the accuracy of the diameter directly relates to its torsional resistance so its extremely important the full set are all the same diameter so as to all act together. If one was slightly oversize then this would be susceptible to more torsional force due to higher resistance than all the others - which would lead to failure,

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Flipping the F1 Timing Gear Damper over again to drive out one of the torsion bars - these sit in square wire edm'd holes under interference fit so as to stop them rotating,

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Flipped over again it starts to emerge,

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Out,

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The Silicon Bronze location bush also removed, these are required since there is angular motion at the ends of the torsion bars,

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Locates clearance fit on the end of bar,

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The torsion bar itself - the torsion section now in full view,

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Because it wasn't fully apparent initially as to whether it was the round section, or the arm extending out to the outer ring gear that was the torsion/flexure section I accurately modeled the part in CAD and did a quick stress simulation as it would with the engine running,

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By making the square section fixed, and also inducing overly excessive force around the axis it became apparent that it was indeed the round torsion bar section that was the zone most in torsion, and not the bending of the arm out to the silicon bronze bush in the outer ring gear,

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The area in Yellow displaying most strain below at full angular displacement,

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So thats pretty much that, interesting part indeed and somewhat like a swiss watch inside when viewed first hand.

It would be wrong not to mention the same item Keith Duckworth came up with on the DFV back in the 70s...

As you can see below, it contains the same torsion bars - called "Drive Quills", the only difference with the DFV assembly was that it served both heads by using a gear on both sides - crank drive to middle gear hub. This was due to it not being designed in from day one and space being at a premium!

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(Image Courtesy of Cosworth Historic - Google Search)

The Gear assembly disassembled below,

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(Image Courtesy of Nick Slade - Google Search)

Drive quills bottom left,

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(Image Courtesy of Nick Slade - Google Search)

Because of this I'd like to dedicate this thread in memory of Keith Duckworth - its amazing to see his brain power still in use some 40years later - Once a good idea, always a good idea.

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(Image Courtesy of Matt Grant @ Modatek)

With all of the above in mind I hope the thread and information here has helped everyone from Casual Viewers, Enthusiasts, F1 fans, Engineers, Designers, Students, and Teachers Worldwide - If you know anyone whom you think would like to see it please share this link.

All pictures are backed up and on prepay hosting so they are not going to vanish anytime soon - hopefully now there is less doubt as to what it takes to create one of the last and in my opinion the greatest ever modern day 20,000rpm Formula One Engines.

All the Best,

Brian Garvey.
Last edited by Brian.G on Thu Aug 24, 2017 12:24 pm, edited 1 time in total.
If you think you cant, you wont, If you think you can, you will

tok-tokkie
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Re: F1 Timing Gear Damper, a closer look

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Yours have been premier posts on the topic of F1 Tech.
Very much appreciated.

Brian.G
Brian.G
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Re: F1 Timing Gear Damper, a closer look

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tok-tokkie wrote:
Thu Aug 24, 2017 8:50 am
Yours have been premier posts on the topic of F1 Tech.
Very much appreciated.
Thank you - my pleasure!

Brian,
If you think you cant, you wont, If you think you can, you will

TristanH
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Re: F1 Timing Gear Damper, a closer look

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What's the "life" of one BG, seeing as it dealing with significant stress?

Brian.G
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Re: F1 Timing Gear Damper, a closer look

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TristanH wrote:
Thu Aug 24, 2017 5:01 pm
What's the "life" of one BG, seeing as it dealing with significant stress?
Not sure, but would guess somewhere between 600km, and 2000km from markings on packages of some parts that came with my v10.

Brian,
If you think you cant, you wont, If you think you can, you will

TristanH
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Re: F1 Timing Gear Damper, a closer look

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I should have snuck it away in my boot when I went to visit!

Was there any similar damper on the engine block that would have been under the heads you sectioned?

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Mudflap
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Re: F1 Timing Gear Damper, a closer look

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Thank you Brian for the beautiful pictures.

Interestingly, this does not appear to have any friction devices, therefore I would not class it as a damper as such - just a soft coupling between the two gears that isolates rather than dampens.

Different incarnations of this, for example the compound gear driving the KERS on the Cosworth CA series incorporated a spring washer to preload the gears against each other so that energy was dissipated through friction whenever relative angular displacement occurred.

I'd also like to mention another one of Duckworth's inventions that is less known but widely used in F1 - the longitudinal dowel pin for locating the bottom of the crank-case.
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J.A.W.
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Re: F1 Timing Gear Damper, a closer look

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Well presented Brian, but the use of 'quill' type/torsion-shaft/viscous-damped/compound gear-train components..
for power-transmission shock/harmonics/torsional vibration control - certainly goes back a ways further yet..

See below for applications in a couple of Napier engines:

http://www.flightglobal.com/pdfarchive/ ... 00609.html

http://www.pigeonsnest.co.uk/stuff/deltic/chapter3.pdf (scoll down to diagram).
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Brian.G
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Re: F1 Timing Gear Damper, a closer look

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@Tristan, I cannot remember what was on the older block, but I don't think there was any - at least I didn't see one in the box of timing gears when stripping head off engine.

@Mudflap, I used the word damper since this is also what all the clutch plate manufacturers call the spring assemblies in the centers of standard automotive clutch discs. Where by a cluster of springs damp the torsional vibrations before reaching the drivetrain. I dont really see the timing gear assembly above as any different - the timing gear on hand is certainly not a friction device however. The oil holes in the hub of the gear directing oil to each torsion bar further confirms that they need cooling since some of the potential/elastic strain energy will be released as heat during continuous cyclical loading and unloading.

@J.A.W, interesting links, and much like how they handled the drive from cam gears, on into camshafts on same engine - four large quill shafts are used.

Brian,
If you think you cant, you wont, If you think you can, you will

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dren
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Re: F1 Timing Gear Damper, a closer look

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Excellent post! I'm wondering how much this affects the timing, and for what duration. Obviously not much to make a major difference.
Honda!

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Mudflap
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Re: F1 Timing Gear Damper, a closer look

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dren wrote:
Fri Aug 25, 2017 1:34 pm
Excellent post! I'm wondering how much this affects the timing, and for what duration. Obviously not much to make a major difference.
This is a bit counter intuitive but timing is generally improved - I'll try to explain:

Crankshaft torsional vibration manifests as a high frequency fully reversed angular displacement oscillation superimposed on the mean motion of the crank gear. The compliant element acts in effect as a high frequency filter which means that the cams see the same mean motion but without the high frequency content - the torsional displacement 'spikes' are greatly reduced such that behaviour is closer to kinematic.

The flexible elements are still stiff enough not to allow significant angular displacement due to mean torque (which in this case is the torque required to turn the cam).

For this reason it was common in the high speed engine era to have another compliant element in the camshaft nose coupled with some form of damping at the rear. For example Honda ran cam quills and viscous dampers at the rear (then replaced the dampers with a pair of gears locking the ends of the cams with respect to each other), Cosworth used a quill shaft protruding into the camshaft ID and also ran viscous dampers at the rear.

Toyota and Mercedes seemed to favor cam roller dampers (which are technically absorbers) as they can be used to dampen a complete order (although they do not work at low engine speeds where the centrifugal force is not high enough to set roller motion).
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Brian.G
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Re: F1 Timing Gear Damper, a closer look

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@Mudflap,

Indeed Honda did run what you mention - I had forgotten, see Images below of what you described so well,

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And the quill drive,

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Very same principal on my own V10 as I have shown below,

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A view down into the hollow cam showing quill shaft location,

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Brian,
If you think you cant, you wont, If you think you can, you will

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Mudflap
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Re: F1 Timing Gear Damper, a closer look

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Thanks Brian,

What is this V10 you have ?
Can you tell if the splines have any crowning on them ?
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Brian.G
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Re: F1 Timing Gear Damper, a closer look

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Mudflap wrote:
Fri Aug 25, 2017 3:45 pm
Thanks Brian,

What is this V10 you have ?
Can you tell if the splines have any crowning on them ?
It is one of the last Cosworth TJV10s - Jag/Redbull - with very low miles,

Splines below,

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Image

Image

Brian,
If you think you cant, you wont, If you think you can, you will

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Mudflap
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Re: F1 Timing Gear Damper, a closer look

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Amazing, did you manage to get a complete unit ?
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