Minimizing chain noise

[Papa]

Hello,
I have been watching this thread with quite some bit of interest. I am particularily curious about the comment by Papa 'that he plans to CNC some sprockets from 7075T6'. I have looked all over Gates website and have never seen the critical dimensioning that goes along with specifying the machining of the sprocket teeth, regardless of which tooth pattern one chooses. Where did Papa get this dimensioning? I would have assumed that this is proprietary information. If this information is available, can we get a link to this info? It certainly is not in the PDF referenced by Miles.
kenkad

I missed this... sorry. (see Miles, I do it too )

I purchased Gates sprockets in the OD I needed. I got lucky, the 75t, shown below, (and the most expensive of the two), ultimately turned out to be a freebie when I complained because it had obviously been repaired. Fortunately, it was still usable and not warped. I have a 9" lathe, so whittling them down to my specs was a cake-walk. These will be duped just as soon as he finishes the G-code. I'll have the CAD profiles and the G-code, but only for 75t (to fit 110mm BCD cranks) and 28t sprockets (for im9 IGH). Please note, the 75t measures 189mm OD, about the same OD as 46t MTB chainring.

[amberwolf]

If sprockets aren't available in the size desired, couldn't you use the epoxy trick AussieJester used on his? Or is that likely to only work on wider pulleys?

[swbluto]

You know, I just want to rip up local parks like a dirt bike. The big problem with dirt bikes, however, is that the 2-stroke or 4-stroke sound is a dead give away. So, I just want to make it so that it won't be obvious it's motorized at a distance of 100 ft. or more. The motor itself is so small that it won't be discernible, and I'm going to partially cover the drive train for protection from "clothes ripping".

I'm aiming a peak wattage of 4 kW out (5 1/3 hp) at 30 mph and a motor RPM of 4000-5000 RPM. I think that might be enough, but I'm worried about the motor heat if it's putting out 500 watts of heat. In reality, I think it's probably not that much of a concern as another motor I had was half the size took about 10 minutes running at that heat wastage level to burn up, and I should only be putting out 500 of watts of heat for a minute or so as the hill should quickly be conquered at 30 mph.

On my scooter, the motor itself really isn't noticeable over 20 feet away at that RPM, but the poorly implemented drive-train sure is (Though it's still a bit quiet on the road.).

[Miles]

I'm aiming a peak wattage of 4 kW out (5 1/3 hp) at 30 mph and a motor RPM of 4000-5000 RPM.

So, you need a motor that will generate around 8Nm of torque, then....

[RWP]

...I use plastic chain in the first stage, which has greatly quieted down my drive train.

Going back to the post above...and chain noise...
How realistic is it to use plastic .25 (#25) or .375 (#35) chain as a first stage with a 3220?
Do these plastic chains have rollers?I have been told that #25 and #35 steel chain have NO rollers.
Thanks,
Roy

[MitchJi]

Hi,

Poly Chain sounds good. The larger pitch (60% larger pulleys) is a disadvantage but the greater load capacity might allow higher loads and lower tooth count which might reduce that disadvantage.

If anyone knows the load capacity of 5mm x15mm HTD compared with 8mm x 12mm Poly Chain or can point me to a direct comparison it would save me looking it up.

Goodyear Falcon PD Belts and Pulleys are a Drop-in replacement for Gates Poly Chain GT2. Their Pulleys Cast are Iron or Steel Construction.
http://documents.kellysearch.com/pub/Ha ... 01/22.html
Click on the image for a full-size display:

Unfortunately Gates and Goodyear Pulleys are useless for ebikes unless 5lb and up driven pulleys in a reasonable size and a limited range of sizes are acceptable:
60t 5 lbs:
http://kscdirect.com/item/GAT%2B7718-10 ... -60S-12%0A

Product Description: 8MX-60S-12 2012 SPKT

Category Hierarchy: Industrial Power Transmission -> Synchronous Metal -> Poly Chain GT2 Sprockets -> 8mm Pitch Sprockets, P.N. Series 7715 & 7718 -> For Belts 12mm Wide

Markets/Applications: Use with Poly Chain GT2 Belts or Poly Chain GT Belts.

Number of Grooves: 60

Material: GI

Belt Note: Sprockets for Poly Chain GT2 belts are available in 8mm and 14mm pitches. Abbreviations used for sprocket material: GI=Gray Iron, DI=Ductile Iron, SiS=Sintered Steel, CI=Cast Iron.

Weight (Lbs.): 5.02

Fortunately Pfeifer Industries sell and produce pulleys in a much wider range of sizes than Gates or Goodyear and aluminum is one option. At $70 per hour custom made (if necessary) even in quantities of one is probably an affordable option.

Stock and Custom Pulley Design / Machining - Prototypes to High Volume

Custom timing belt pulley manufacturing is our specialty. We also stock an extensive inventory of 5mm HTD, 5mm PowerGrip GT, 8mm HTD, 8mm PowerGrip GT2 or 8mm PolyChain GT pulleys.

As a master distributor for Continental ContiTech, we carry a large inventory of timing belts and can fulfill any other power transmission belting needs.

http://www.pfeiferindustries.com/capabilities.htm

Bourn & Koch CNC Gear Hobbing
~Hobs and tooth ranges currently available
* 5mm HTD, (17 Tooth through 200 Tooth)
* 5mm PowerGrip GT, (16 Tooth through 200 Tooth)
* 8mm HTD, (14 Tooth through 140 Tooth)
* 8mm PowerGrip GT2, (22 Tooth through 140 Tooth)
* 8mm PolyChain GT, (14 Tooth through 140 Tooth)
* Additional hobs available upon request

http://pfeiferindustries.com/submit_design.htm

Material Type: 6061 Aluminum

Also FYI Contitech SynchroChain is a direct replacement for Gates PolyChain GT.

Pfeifer Industries and Continental ContiTech announce their partnership to sell the Contitech SynchroChain timing belt as a direct replacement to the Gates® PolyChain GT® timing belt.

Pfeifer has an the nicest Belt Length/Center to Center Distance Calculator I've found plus some handy pdf's:

Belt Length and Center to Center Distance Calculator

http://www.maxtorque.com/calctool/cente ... startx.asp
http://www.pfeiferindustries.com/timingbelt_pulleys.htm
http://www.pfeiferindustries.com/timing ... charts.htm
Two of the Four Pitch Diameter (P.D.) & Outside Diameter (O.D.) Charts
http://www.pfeiferindustries.com/pdfs/5 ... d%20OD.pdf
http://www.pfeiferindustries.com/pdfs/8 ... and_OD.PDF

And some excellent Technical information and downloads:
http://www.pfeiferindustries.com/power_ ... ations.htm

How realistic is it to use plastic .25 (#25) or .375 (#35) chain as a first stage with a 3220?

I think Poly Chain might be a better choice if you have some additional space. Matt said 26t 5mm x 15mm HTD pulleys with high belt tension worked for connecting dual 3220's (13 belt teeth contacting the pulleys) so something like 20t/60t with shafts about 6" apart would probably work (?) or maybe even something like 16t/64t (?).

[dbaker]

http://www.cometkartsales.com/store/belts/belts.htm

aluminum 5mm pulleys up to 144 tooth

[Papa]

Goodyear Falcon PD Belts and Pulleys are a Drop-in replacement for Gates Poly Chain GT2.

Indeed, but here's what Gates had to say about Falcon PD belts (PDF at bottom of post):

If anyone knows the load capacity of 5mm x15mm HTD compared with 8mm x 12mm Poly Chain or can point me to a direct comparison it would save me looking it up.

I have the numbers somewhere, but haven't unearth'em... yet. The best I can do short-term, is this:

Poly Chain GT Capacity
- Approximately four times the horsepower capacity of HTD®

Poly Chain GT2 Capacity
- Approximately thirty percent more horsepower capacity that Poly Chain GT

http://www.gates.com/ptpartners/file_di ... elts%2Epdf

Notice how the chain's HP rating drops sharply as RPMs increase.

[Papa]

My previous post was created piecemeal, so I'd recommend reloading to avoid missing any late additions. Spare me please... i'm slow

[Miles]

How realistic is it to use plastic .25 (#25) or .375 (#35) chain as a first stage with a 3220?

I think Poly Chain might be a better choice if you have some additional space.

You only need to move to PolyChain if PowerGrip isn't capable of handling the torque. It's not something you'd normally need for the first reduction stage. 8M PowerGrip has significantly greater capacity than 5M.

[liveforphysics]

This chart definately looks like it was written by a company selling belts. lol

In years of working on and playing around shifter karts, I've never seen a #219 chain fail, and they spin them to 19,000+rpm on the direct drive 100-125-150cc karts, pumping 35-50bhp through them for many many hours of use on a chain, and they still simply aren't a reliability problem. (this is similar to #35 size chain, but with a finer pitch)

Then of course dirtbikes like my KTM pump 73rwhp through a 520 sized chain, never getting a drop of lube or cleaning (x-ring sealed chain), get packed with rocks and mud and sticks, and just power through everything you throw at them and never give an issue for years of abuse and neglect, and I considder myself an expert at neglect and abuse.

Or even factory 180-190bhp superbikes running 530 or 540 sized chain, and lasting 10,000miles before the aluminum sprockets wear down, but the chain is still ok, it just gets replaced with the sprocket replacement so they can both break-in and seat together.

[dbaker]

Is a similar graph available to compare 5mm to #25 chain at speeds up to 15,000 rpm? Are you better choosing a wider 5mm compared to a narrower 8mm belt for RC motor primary operation?

[Miles]

Are you better choosing a wider 5mm compared to a narrower 8mm belt for RC motor primary operation?

Good question. You can get either belt cut to the exact width required and custom pulleys. Wider belts need more careful alignment and put greater stresses on the bearings. With regard to the best efficiency, I'm not sure where the changeover point is.

[liveforphysics]

Since sometimes a picture or video can be better than a thousand words... For all the folks who beleive that chain vs belt HP rating graph...


This is a rotax superkart. On a 9" diameter rear tire, you're looking at 5,600rpm on the BIG sprocket at the rear axle at peak speed (150mph)!!! A conservative 20-25,000rpms on the front sprocket, and handling 70bhp, and the chain drive setup is extremely reliable, so reliable that it's simply not a concern for failures.

Do you really think any e-bike appliction would ever need a stronger chain than simple #219??? How many belts have we seen skipping or broken or whatever else, and who has ever had #219 (or even #35) fail for anything? You and throw graphs and charts away, the motorsports world has done 50+ years of real-world testing, and the proof is inherent.

[Miles]

Belts are great - you can't use them 'naively', as you can with chain, though......

[bandaro]

so, if i was going to walk into my local store, to get a strong (peaking at around 7-8hp from stall) and relatively quiet if possible chain, what would be a good brand and/or type?

people are throwing numbers around that i have no clue what the correspond to, but im sure if i have a list of possible chains the guys at the store will have them or something similar. so whats a chain im likely to find in-store that will suit the application, or any brands to avoid?

[liveforphysics]

so, if i was going to walk into my local store, to get a strong (peaking at around 7-8hp from stall) and relatively quiet if possible chain, what would be a good brand and/or type?

people are throwing numbers around that i have no clue what the correspond to, but im sure if i have a list of possible chains the guys at the store will have them or something similar. so whats a chain im likely to find in-store that will suit the application, or any brands to avoid?

Go to a kart shop, and tell them you would like #219 chain, with a rear sprocket of XX teeth, and a front sprocket of X(X) teeth.

Here are some dimensions of various sprocket sizes, and a clear illustration of the advantages of #219 over it's cruder pitched sister, #35.

The only drawbacks to #219 is the front sprockets are generally setup for slipping on a clutch drum spline and retained with a circlip rather than set onto a shaft with a keyway and/or setscrew. This means an extra $40 or so at a local machine shop to turn a little shaft adapter for you, and tig weld the sprocket upon it. An inconvience, but not a deal-breaker.

http://www.tsracing.com/Techtips/TSchain.html

[Solcar]

...I use plastic chain in the first stage, which has greatly quieted down my drive train.

Going back to the post above...and chain noise...
How realistic is it to use plastic .25 (#25) or .375 (#35) chain as a first stage with a 3220?
Do these plastic chains have rollers?I have been told that #25 and #35 steel chain have NO rollers.
Thanks,
Roy

Roy, you're welcome. The plastic chain tends to be self-lubricating and that might be able to obviate rollers, especially on plastic sprockets. Based on my scant knowledge of the high power RC motors, the power level there is probably too high for plastic chain. My #25 steel chain has rollers.

[dbaker]

so, if i was going to walk into my local store, to get a strong (peaking at around 7-8hp from stall) and relatively quiet if possible chain, what would be a good brand and/or type?

people are throwing numbers around that i have no clue what the correspond to, but im sure if i have a list of possible chains the guys at the store will have them or something similar. so whats a chain im likely to find in-store that will suit the application, or any brands to avoid?

Go to a kart shop, and tell them you would like #219 chain, with a rear sprocket of XX teeth, and a front sprocket of X(X) teeth.

Here are some dimensions of various sprocket sizes, and a clear illustration of the advantages of #219 over it's cruder pitched sister, #35.

The only drawbacks to #219 is the front sprockets are generally setup for slipping on a clutch drum spline and retained with a circlip rather than set onto a shaft with a keyway and/or setscrew. This means an extra $40 or so at a local machine shop to turn a little shaft adapter for you, and tig weld the sprocket upon it. An inconvience, but not a deal-breaker.

http://www.tsracing.com/Techtips/TSchain.html

Luke,

Since this thread is "focused" on noise can you offer some advice on sprocket size and noise for #35 chain (on your ebike) and #219 chain? Is there a recommended minimum size and speed for noise control? I remember Gary complaining about the #35 chain noise on his Dahon but I don't remember what his motor sprocket was. I am clear that the #219 has a distinct advantage over #35 for achieving a greater speed reduction.

That kart video was amazing! 150 mph! It has been quite a while since I was in a kart but don't they have pretty quick steering?

Dave

[Papa]

Do you really think any e-bike appliction would ever need a stronger chain than simple #219??? How many belts have we seen skipping or broken or whatever else, and who has ever had #219 (or even #35) fail for anything? You and throw graphs and charts away, the motorsports world has done 50+ years of real-world testing, and the proof is inherent.

And speaking as a pro wrench, one of the biggest money-makers of the 70's and '80's was timing chains - typically at 25k to 40k they had either wore-out or failed completely - and not from lack of lubrication or tire smokin' abuse either. I bought a '73 Civic and drive it 103,000, negligent miles on its original 'belt'. But examples aside, the original issue the OP raised was not one of reliability or longevity... but noise. So what's your suggestion(s) to his dilemma?

[Papa]

CONTACT PROBLEMS IN ROLLER CHAIN DRIVE SYSTEMS

"Even if the velocity of the driving sprocket is constant the driven sprocket velocity will fluctuate. This is known as the polygonal effect and it is the responsible for the transverse and longitudinal vibrations that develop in the chain.The excitation resulting from the impact of the roller when it seats on the sprocket and the polygonal effect are the responsible parts for the noise and vibration of the roller-chain drive."

Source: http://fluid.ippt.gov.pl/ictam04/CD_ICT ... _12569.pdf

[Miles]

Thanks for that Papa.

I'll post this one again, for those that missed it before: http://chain-guide.com/basics/2-2-1-chordal-action.html

[liveforphysics]

Do you really think any e-bike appliction would ever need a stronger chain than simple #219??? How many belts have we seen skipping or broken or whatever else, and who has ever had #219 (or even #35) fail for anything? You and throw graphs and charts away, the motorsports world has done 50+ years of real-world testing, and the proof is inherent.

And speaking as a pro wrench, one of the biggest money-makers of the 70's and '80's was timing chains - typically at 25k to 40k they had either wore-out or failed completely - and not from lack of lubrication or tire smokin' abuse either. I bought a '73 Civic and drive it 103,000, negligent miles on its original 'belt'. But examples aside, the original issue the OP raised was not one of reliability or longevity... but noise. So what's your suggestion(s) to his dilemma?

Honda is an excellent example They used belts for a few decades because they were silent. Right now, Honda doesn't use a belt for any engine (at least that I'm aware of). They moved to Honda silent chain with the advent of the F20C in the Honda S2000. Reason? Belts become/became pretty substantial reliability problems with monster cam lobes and stiff triple valve spring setups. Toda and other companies released various kevlar timing belts and things to relieve the problem, but things would still get pretty sloppy by around 5-10k miles of running on big lobes/springs.

After the move to silent chain (a chain with no rollers or contacting pins to click), folks get multi-hundred thousand miles and the chains are still like new. You can run as big of cam/spring combo as you like on the F and K-series engines and never worry about belts shredding or skipping teeth etc. You do need to change to a smarter chain-tensioner design though... I hate the Honda auto chain tensioner setup... But the chain/sprockets themselves are outstanding, extremely quiet, pretty fine pitched, and handle loads of RPM and power. I put mine through 10,000rpm drive sprocket speeds dragging along some pretty brutal lobes against mean triple springs, and every time I tear into the engine, the chain looks brand new.

[swbluto]

Here's a page on the silent chain.

http://chain-guide.com/applications/1-6 ... chain.html

From what I read, it states that it requires an oil bath and an "automatic tensioner". Those would seem to be difficult if not impractical to implement on an ebike. Also, where would one find sprockets for these things (Since they have their own special sprockets)?

Btw, I'm trying to find a good graph or chart on RPM and noise. I saw one in a PDF once (I think it was comparing silent chain with regular chain; heh, I should just scour the ramsey site.), though it was showing a chart for a pretty large chain type. I'm going to try to predict chain noise based on that. I think my last estimate was something like 70-75 dB, but it was just a guess.

[Miles]

If minimizing noise is important, just avoid using chain for the first stage of a two stage drive.

If you use chain, go with the largest drive sprocket (most teeth) that's practical.