Cyclone motor noise reduction in trike mid-drive builds

[solar.g]

Just a few thoughts about Cyclone motors, controllers, gearboxes and noise:
I'm part of a group of riders who, between them, have a dozen or so Cyclones in bikes/trikes.
They each have their own "sound signature", which we are at a loss to quantify to a particular cause/source.
My question is:
What creates the noise in a Cyclone motor/gearbox installation - is it the planetary design, the straight-cut gears, the gears being metal, lubrication, tolerances, motor noise created by controller design, the way it's mounted in the vehicle?
ie: to solve a question raised in another thread (http://endless-sphere.com/forums/viewtopic.php?f=28&t=56957&p=849650#p849650), is it possible to make a Cyclone planetary gearbox quiet (without external sound-shielding, which AFT use), from an engineering-design point of view? Even if plastic gears "work", will they handle the power? Would different metals/alloys for the planetary gears help with wear and/or noise?
What is the best controller to drive a Cyclone from a noise point of view?
Internal (no, for various reasons), Kelly, Lyen, sine-wave, any other?
For trikes in particular, Cyclones are a great mid-drive solution.
They're just noisy.
Like to understand the cause of the noise, and how to fix it, better.

 

[amberwolf]

What creates the noise in a Cyclone motor/gearbox installation - is it the planetary design, the straight-cut gears, the gears being metal, lubrication, tolerances, motor noise created by controller design, the way it's mounted in the vehicle?

Yes. (all of the above)

is it possible to make a Cyclone planetary gearbox quiet (without external sound-shielding, which AFT use), from an engineering-design point of view?

Dunno about the cyclone gearbox specifically, but yes, it is possible to make quieter gearboxes; you'd likley have to look at existing ones that are already quiet and see what they did to get it there.

Or find the specific source of noise in your specific application/parts and then find fixes for those noise types.

Even if plastic gears "work", will they handle the power? Would different metals/alloys for the planetary gears help with wear and/or noise?

There's been lots of discussion about that over the years here on ES and elsewhere, with no catchall conclusions. But your best bet is to look up the threads about MAC / BMC gearing changes over the years.

What is the best controller to drive a Cyclone from a noise point of view?
Internal (no, for various reasons), Kelly, Lyen, sine-wave, any other?

Would depend on the specific motor itself, most likely. A controller that is designed and tuned around running a specific motor would proably be quieter and more efficient in operation as a unit.

 

[solar.g]

Thx for the tips.
I've tried all the usual things - gear oil/grease slurry (helps a bit), checking mounting for resonances (not yet finished investigating).
My 2 trikes run Lyen 3077 9-FET controllers, so don't know if the controllers have different noise signature to Kelly or internal Cyclone/Headway ones.
Do know many '000s of km does help wear in the gears; only have 2000 on mine so can't conclude anything yet.
Plastic gears would be nice to try, given that I'm only running 200W or so through them (should be able to handle that power).
Will watch discussions elsewhere and if anyone offers plastic gears for sale, I'll try them.

 

[maeda256]

I think it is gear noise.
And I think overload for this gear because bit silent at half throttle.
(I think this motor is designed for 650W. But I (and ours!) drive at 2kW or so)

I hate this gear noise, Finally I remove this planetary geabox, and
change to 2 stage cogged belt. It is silent.

 

[kriskros]

I have been using a 1600w cyclone with a Nuvinci hub on my wood bike...using a thick Moly grease reduced the noiuse slightly...the noise is from the, metal gears... there is a plastic that ciould handle the torque... it is called TORLON. very expensiuve... it comes in powder, sheet or rod...if you used the current gears as a model,gears could be cut on a lathe....Mac gears can take the torque from at least a 48v,20 amp battery. I have aPuma[Mac] with green gears that have over 3000 miles and still going.i.. the original whte nylon didn't las t 300 . even plastic gears make some noise,bur not nearly as much as metal...aklso , the plastic gears do become VERY quiet after 6 or 700 miles...i asked Cellman what the material was but he didn't know. I think the plastic gears used other motors eg,bafang mac ect are molded

 

[k-harvey]

I have many cyclone motors some that have ruined internal controllers.--a fault with these.
Most of these gear box's are reasonably quite bar one -its now cleaned out with no sign of wear what shall i do with it
going by what I've read its no use taking gears out perhaps creating an oiler system ? .the quite one are the same inside ---metal. At the moment as its controller has died i can do without it. i don't believe any plastic could do the job here.

 

[spinningmagnets]

I can only guess, but my first efforts would be to custom-cut helical-cut gears. Having all metal gears mean the noisy Cyclone gearboxes can take a lot of power. I have seen gears with a significant angle to the teeth, but the Bafang BBS02 and the Bosch both have only a slight angle, so it doesnt take much to make a huge difference in sound.

Second would be to switch the planets to a hard plastic (sun gear would remain metal), some type that can absorb a little of the impact of the initial contact of the teeth. The BBS02 also has a long metal gear that is on the motor shaft, so it has two of its teeth engaged at any given time. Of course making ther Cyclone gearbox longer to hold longer helical gears would be an extensive mod.

 

[k-harvey]

Thank you all , on a much closer inspection planetary gears teeth have slight blur to one side-- this is it. Will contact Br paco for parts , etc -- realy the gear box's have been good its the controllers , br paco has offered good deal for what they say is 650w( i proved it much less) with ex controller & unless one of these local electronic friends I've made recently who i gave each a 500w motor to play with i'll have to take Br Paco deal ----anyway we don't live on a mountain now so less a power won't be noticed as much.

 

[k-harvey]

Also found a real sticky type grease that nI'll put in all the cyclone gear box's i work on.

 

[Samer]

I think it is gear noise.
And I think overload for this gear because bit silent at half throttle.
(I think this motor is designed for 650W. But I (and ours!) drive at 2kW or so)

I hate this gear noise, Finally I remove this planetary geabox, and
change to 2 stage cogged belt. It is silent.

do you have photo of your 2 stage cogged belt?

cheers

 

[gman1971]

I have a 6 kW Cyclone trike and mine is only noisy when the motor is spinning at full RPM (regardless of gears), at low speed the motor is very quiet, but then again, you probably have the older Cyclone kits with steel gears. The newer Cyclone 3000W kit has nylon gears so that has quieted it down quite a bit.

However, I have the same issue on mine at high motor RPMs, and the noise seems to come from the rear and not from the front BB (which is where the motor is mounted) So I would think its in part due to the chain being so tight and the vibration being transmitted to the under the seat idler and the frame resonating like a tuning fork... my eBike with a Cyclone 3000W is much quieter, not sure why...

I think something like urethane dampers or CF dampers would probably help quite a bit absorbing the unwanted vibrations...

G.

 

[k-harvey]

ne wonders as with years ago for a car with a noisey diff we were told stuff it full with banana skins ....for the amount of dismantling ive done for this problem think ill try it.