Minimizing chain noise

[swbluto]

So I was using Gate's designFlex to design a belt system and they said the drive would be 91 dB at 8M for GT2 and 86 decibel at 5M at 5000 motor RPM. The driving pulley was 22 teeth and the receiving pulley was 80 teeth.

That seems as loud as a chain is rated at that speed. (A silent chain would be rated at 70-75 dB)

 

[MitchJi]

Hi,

The only problem now is finding available "silent chain" sprockets.

Why not use their calculator and then ask Ramsey for a quote on sprockets?
http://www.ramseychain.com/chain_calc.asp

Isn't silent chain the next best option after a belt for noise?

For me?... no. By going with belt, I eliminate the infamous 'leg tattoos' and noise... and trimmed-off 1.8 pounds of oily baggage in the process!

After a belt for noise. In other words the quietest option if he decides against a belt.

 

[dumbass]

Many years ago when I was much younger and more foolish I bought a new Ford Pinto. Actually I eventually owned 2 of them and a friend had one as well. They had a "timing belt" to drive the cam. This damn belt had to be replaced every 12k to 15k miles. My friend would always call me to help do his. So between the 3 cars I was replacing a belt at least every 3 months. Now I have owned a lot of cars that had standard metal timing chains and in hundreds of thousands of miles I never replaced a metal timing chain.

How odd?? I was the head wrench on the Parker brothers 2WD, rear engine buggy class during peak, Firecracker 250 offroad racing season in Barstow, California. VW motors were dumped in favor of 2300cc Pinto motors. I would religiously inspect the timing belts prior to every event, and we not only had NO mid-race belt failures, but frequently put 2 and 3, 250 mile races on the same belt. Further, belt technology has vastly improved in the last 15 years, so the 'Pinto' example is not-at-all representative of today's belts.[/quote]


How odd! I was engineering manager of a 4 billion dollar company so I think I have the common sense to identify a timing belt falure and the frequency of it's falure. I have to question why you felt the need to inspect the timing belt before every event. I would hardly consider 500 to 750 miles on a timing belt as something to brag about. Of course an engine under the stress of racing is much more likely to have falure but 750 mile......Come on now!! By the way I was speaking of the 1600cc motor but I don't think it makes any difference.

you are correct, timing belts have come a long way in 15 years. I am confident they would do fine in most applications on a bike even an ebike. The 2 biggest problems I see with using a belt system as a retrofit is they can't be laced into the frame unless you have a break-a-way on your drop out. Many average people may also have a problem truing a bely system whereas, any dummy can setup a chain system.

I admit I have given a lot of thought of installing a belt system but I don't plain on buying a new bike with a break-a-way drop out just so I can test a belt drive. I have also looked at the Ramsey silent chain but for now I'm willing to listen to the noise and let someone else go first. http://www.ramseychain.com/prod_sc_conv_multi.asp?base=2

 

[Miles]

So I was using Gate's designFlex to design a belt system and they said the drive would be 91 dB at 8M for GT2 and 86 decibel at 5M at 5000 motor RPM.

Where is that info shown, SW? It's not available in my copy of DesignFlex....AFAIK :?

 

[Papa]

How odd! I was engineering manager of a 4 billion dollar company so I think I have the common sense to identify a timing belt falure and the frequency of it's falure.

By the way I was speaking of the 1600cc motor but I don't think it makes any difference.

No wonder you had breakage,.. the 1600 was chain... not belt. Only the 2.0 and 2.3 had belts.

Don't believe me?... http://www.autopartsdeal.com/catalog/?N=0&uts=true&Ntt=1973+Ford+Pinto+Cloyes+Timing+Chain

 

[MitchJi]

Hi,

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

Ok, let's sum up:

PolyChain has a significantly higher torque handling capability than PowerGrip. The belts are also much more expensive than those for PowerGrip.

Moving from 5M PowerGrip to 8M PowerGrip is itself a significant change in torque handling capability.

…as a first stage with a 3220?

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.

So for a 3220 primary stage you would choose PowerGrip instead of PolyChain? Why?

One advantage of the increased power handling of PolyChain is you could use smaller pulleys. If it really is 4x you could use pulleys 1/2 the size (same pulley size as 4mm!) and have roughly twice the power handling.

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.

I used the Pfeifer Industries Calculator and came up with the following (tim = teeth in mesh, belt = belt length and c/c = shaft center to center distance):

   5mm tim           	belt    c/c
        12 (30t/90t)	 665 mm  6.93"
        14 (34t/102t)	710 mm  6.96"
        
    8mm tim           	belt    c/c
         9 (22t/66t)  	720 mm  6.89" 
         9 (23t/69t)  	720 mm  6.52"

The 102t 5mm pulley is about the same size as a 61t 8mm pulley and it has 14 tim vs 9 tim (about 60% more) so 8mm would need to have a 60% increased power handling to break even on pulley size.

BTW I'm not sure how much I trust the Gates specifications. Despite the spec differences between HTD and PowerGrip Matt said in practice he didn't notice a substantial difference.

Does anyone know the quality of Conti Belts vs Gates Belts (in the 5mm HTD, PowerGrip GT and PowerGrip GT2 they have a much better selection of belt lengths).

 

[Miles]

One advantage of the increased power handling of PolyChain is you could use smaller pulleys. If it really is 4x you could use pulleys 1/2 the size (same pulley size as 4mm!) and have roughly twice the power handling.

You need to compare PolyChain with PowerGrip GT3. 22t is the smallest recommended pulley for both. I've used a 16t pulley with 8M PowerGrip but I doubt if the Carbon PolyChain is as tolerant...........

 

[MitchJi]

Hi Miles,

You need to compare PolyChain with PowerGrip GT3. 22t is the smallest recommended pulley for both. I've used a 16t pulley with 8M PowerGrip but I doubt if the Carbon PolyChain is as tolerant...........

Thanks!

Did the 16t pulley with 8M PowerGrip work well?

Is the recommended number of teeth the same for for both 5mm and 8mm PowerGrip?

Thanks Again!

Mitch

 

[Miles]

No problems, so far...

18t is the smallest recommended for 5M

 

[swbluto]

http://www.ajdesigner.com/phptorque/torque_equation_force.php

I'm using this to calculate force because it's easier. Anyways, I was calculating the force on a #25 chain using a motor torque of 20 NM and a #25 chain sprocket of 16 teeth (Which according to http://www.amazon.com/Steel-Roller-Sprocket-Single-Diameter/dp/B000FP9YSO has a pitch radius of around .65 inches), and it calculates 272 lbs. The working rating of #25 is 140 pounds according to http://en.wikipedia.org/wiki/Roller_chain, suggesting that it wouldn't work. Is my physics reasoning wrong or is matt not getting anywhere near a motor torque of 20 NM and using a larger motor sprocket?

So far, it seems like the only competitors in for a "high motor torque" drive is 8M HTD, GT and PolyChain variants with a driving pulley of at least 20, silent chain and #35 and above.

If I tuned down the motor torque to 12 Nm, I could probably get away with a 5M HTD 25mm belt and a 22 tooth driving pulley. I also could get away with a #25 with a 24 tooth driving sprocket and tuning down the torque to 12 NM or so. But, at that point, I might as well just go with a 5303 hub. It wouldn't be useful for dirt biking, but it'd get me up hills at 30+ mph. But, if I "can't go"(without reprehension) biking in sensitive areas due to chain noise anyways, that really doesn't matter.

 

[Papa]

Perfect solution for you 'chain' advocates... :lol:

 

[dbaker]

Do we have good data for 3220 torque to use in these calculations? Matt's bicycle tire on the trike seems to break loose and limit the torque that the drive sees. A downhill bike with a larger tire (and AJ's rig for sure) and the greater weight distribution on the rear drive wheel might well put more torque on the drive.

 

[dbaker]

What are the practical torque limits of the #25H chain?

 

[liveforphysics]

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.?

Don't be scared away by that. lol. Look at charts for EVERY type of chain, including all the stuff used for karting, motorcycles etc etc. They all list that they require an oil bath...

They list oil-bath only so they can list the operational times of the chain to be like 5 years of 24-7 operation or whatever crazy wear condition claims they come up with for industrial applications.

For EV applictions, treat it like your bicycle chain or any other chain, maybe a dribble of oil here every couple weeks.

 

[liveforphysics]

The working rating of #25 is 140 pounds according to http://en.wikipedia.org/wiki/Roller_chain, suggesting that it wouldn't work. Is my physics reasoning wrong or is matt not getting anywhere near a motor torque of 20 NM and using a larger motor sprocket?

Remember, working load on a chain means it runs for x years under those loads before it wears out from friction on the pin-bush pivots... If you were setting up to run a 24-7 generator with it for years, then maybe stay under 140lbs... If you're building an EV, as long as you don't push it till it snaps, who really cares if you have to swap out a $10 chain yearly.

 

[swbluto]

The working rating of #25 is 140 pounds according to http://en.wikipedia.org/wiki/Roller_chain, suggesting that it wouldn't work. Is my physics reasoning wrong or is matt not getting anywhere near a motor torque of 20 NM and using a larger motor sprocket?

Remember, working load on a chain means it runs for x years under those loads before it wears out from friction on the pin-bush pivots... If you were setting up to run a 24-7 generator with it for years, then maybe stay under 140lbs... If you're building an EV, as long as you don't push it till it snaps, who really cares if you have to swap out a $10 chain yearly.

Thanks for the assurance. I was a little worried because the belts also have a rating, but it seems like they actually instantly break when you surpass it by a certain amount and the replacement costs add up over multiple belts. I didn't want to have that same experience with a bike and have to detune it to lame torque levels since I'd have to replace it too frequently (Like every 10 hours of operation).

 

[Papa]

Luke,

I'm no chain expert, but the greater number of sliding parts in the 'silent' chain, suggest to me that constant lubrication is critical to service life. I mean, if the many silent chains that I've replaced back in the 70's and 80's religiously puked at 1/3 the engine's expected life, then It'd be a safe bet that the dry running service life of that type of chain would be a fraction of what I was seeing when it was constantly bathed. The 'heavy duty' or 'racing' (vehicle) timing chains were double roller. They definitely lasted longer, but you could heard it talking every time you twisted the key. And you and I both know, that starving a chain, any chain, not only exacerbates the noise by an annoying amount, but accelerates sprocket wear too - so it's not just a $10 chain replacement, but the $30 cogs also,.. AND the labor associated to replace.

 

[MitchJi]

Hi,

Do we have good data for 3220 torque to use in these calculations? Matt's bicycle tire on the trike seems to break loose and limit the torque that the drive sees. A downhill bike with a larger tire (and AJ's rig for sure) and the greater weight distribution on the rear drive wheel might well put more torque on the drive.

What are the practical torque limits of the #25H chain?

I run extra heavy-duty #25 chain from scooter parts.com. That chain is freaking DIRT CHEAP! I beat the crap out of that chain and in over 1,000 miles, have not worn one out, yet. But, it is so cheap, who cares!

Matt

Matt has built or sold a combined total at least 10 dual stage drives all of which used #25 chain on the second stage with no reported failures. Some of these were 3220's powered and used #25 chain on both stages.

He has also sold a small quantity of 3220 powered single stage drives with #25 chain, with no reported failures.

I'm no chain expert, but the greater number of sliding parts in the 'silent' chain, suggest to me that constant lubrication is critical to service life. I mean, if the many silent chains that I've replaced back in the 70's and 80's religiously puked at 1/3 the engine's expected life, then It'd be a safe bet that the dry running service life of that type of chain would be a fraction of what I was seeing when it was constantly bathed. The 'heavy duty' or 'racing' (vehicle) timing chains were double roller. They definitely lasted longer, but you could heard it talking every time you twisted the key. And you and I both know, that starving a chain, any chain, not only exacerbates the noise by an annoying amount, but accelerates sprocket wear too - so it's not just a $10 chain replacement, but the $30 cogs also,.. AND the labor associated to replace.

Modern silent chains (in Honda's for example) routinely last over 100k miles (which is why they use an automatic chain tensioner). I think its reasonable to assume that on an ebike or scooter with typical maintenance (a little oil when you break it out in the spring ?) longevity won't be an issue and the sprockets should outlast several chains.

I think belts are the ideal choice for a first stage reduction with a high speed motor on an ebike or scooter but that doesn't mean that they are the best solution for everyone or every installation:
http://www.pfeiferindustries.com/timing_beltsadvantages.htm

Disadvantages:
Note: Our own experience has shown, that the belt drive is not perfect in every situation when comparing it against a chain drive. Being able to recognize belt drives short comings helps us to educate our customers in making the right decisions on their particular applications needs.
* Availability of numerous chain sizes allows for the use of smaller pitch diameters and/or number of teeth while achieving the desired ratio
* Higher speeds and power capacities
* Detachable chain links make installation easier in some instances
* No slippage
* Higher drive ratios at shorter center distances
* Lower bearing loads
* Less affected by temperature or humidity
* Less affected by oil and grease

Advantages:
* Precision registration and timing with no loss of high torque carrying capability
* Minimal vibration and chordal effect
* Positive slip proof engagement
* Wide speed range, especially important when the entire speed range is developed from a single source
* Virtually no elongation (stretching) due to wear
* High mechanical efficiency, as much as 98% with properly maintained CTD, HTD or STD profile systems. By contrast, chain drives are in the 91-98% efficiency range, while V-Belts average in the 93-98% range.
* Power transmission efficiency is not lost with use
* Clean operation, no need for lubrication
* Reduced noise
* Long, dependable trouble-free service
* Excellent abrasion resistance
* Rust resistant
* Resists chemicals and contaminants
* Increased drive design options
* Safety issues
* Economical operations:
o No need for expensive drive enclosures
o No need for lubrication systems
o No need for tensioning devices
o No adjustment needed due to stretch or wear
o No cost for lubricant or disposal fees
o No worn sprocket replacement
o No ongoing maintenance costs for roller chain
o Energy savings
o Reduced costs associated with "downtime" on top of lost productivity

 

[Nanoha]

Hey guys, what about ideas to muffle the noise on an existing chain setup?

Like a fully enclosed chain guard or something? At least when the chain snaps at 20kw
you won't be missing a body part or two.

 

[REdiculous]

Hey guys, what about ideas to muffle the noise on an existing chain setup?

Turn the motor off. :lol: