Help finding a solution to Bafang gear stripping

[docnjoj]

Alloy sounds like metal to me!
otherDoc

[Knuckles]

docnjoj,

Just ask Keywin for some metal ones.

I had thought you already purchased them. GOSH!

Is he sold out already?

btw ... I love your description ... "Peanut Butter Jelly" Time!
"Tricruiser w/Bafang geared brushless motor(temporarily P-Nut butter geared) and wife rides Bike-e with Crystalyte brushed front motor. I run 48 volts new Ping now and it is truly awsome! She got the Ping Batt, 36 v10ah, and only uses 50% DOD or lessl!!! Stuff hanging around: 16" welded alloy brushed Crystalyte wheel (409 I think) and MY1018 in trailing arm w/3 speed hub! Brushed Crystalyte goes back on Trike tomorrow! Hope the P-Nutt butter can be turned back into gears again! - otherDoc"

[docnjoj]

Donknow? I'll try!
otherDoc

[docnjoj]

Anybody tried a steel gear with nylons yet????????
otherDoc

[docnjoj]

We from New York know how to handle storm troopers! Can U spell UZI!
otherDoc

[voicecoils]

Anybody tried a steel gear with nylons yet????????
otherDoc

Nope. I'm still waiting for my steel set to arrive.

I'd rather run 3 for max reliability and power handling, but I might try torture testing 1 steel 2 nylon at 80V close to home to see what happens.

[Knuckles]

I'm still waiting for a metal gear for my Bafang also. I am sure 1-Metal and 2-Nylon will be fine although 3-Metal gears can't hurt.

Meanwhile Mark H (teamhybrid@btinternet.com) sent me a bunch of metal gears for his PUMA motors.

PUMA_Metal_Gears.JPG (72.08 KiB) Viewed 698 times

I placed 1-Metal gear in the PUMA I laced and tested at 72V.
Very quiet and very much torque. Fantastic motor. I am hooked.

Laced_PUMA.JPG (41.62 KiB) Viewed 699 times

I used a (14-gauge) dbl-cross and weaved lace pattern in a 26" dbl-wall RHYNO LITE rim.
And I added a 7-speed cassette also.

PUMA_w_7-Speed.JPG (56.48 KiB) Viewed 699 times

Also built a custom harness to the Infineon using Andersen connectors.

The three PUMAs Mark sent me are already sold. Some with all 3-Metal gears at client request.
But Mark has plenty so contact him for motor pricing.

So what's good (Metal gears) for the (daddy) PUMA is certainly good for the (baby) Bafang.
I would say at least 1-Metal gear is mandatory at 72V at this point (both for PUMA and Bafang).

-K

[docnjoj]

Puma/BMC are probably the most powerful geared motors around now! Way more than i need! Even for a "largish gentleman" such as myself!
otherDoc

[voicecoils]

My metal gears from Keywin arrived today at work.

None of them spin smoothly. Varying degrees of 'lumpyness' when spun. Each have enough friction to stop almost as soon as my finger spins them around.

May have to look into pressing in new sealed bearings, not a complete deal breaker though

I'll pop them in tonight.

(crappy iphone picture)

[recumbent]

None of them spin smoothly. Varying degrees of 'lumpyness' when spun. Each have enough friction to stop almost as soon as my finger spins them around.

Don't fret till they are broken-in. There are globs of grease inside, and if you spun them cold it's even worse.

Good luck and I'm sure you'll keep us updated on the progress. We had our first snow yesterday that stayed on the streets, hope your better.

[voicecoils]

None of them spin smoothly. Varying degrees of 'lumpyness' when spun. Each have enough friction to stop almost as soon as my finger spins them around.

Don't fret till they are broken-in. There are globs of grease inside, and if you spun them cold it's even worse.

Good luck and I'm sure you'll keep us updated on the progress. We had our first snow yesterday that stayed on the streets, hope your better.

It feels like the ball bearings are under too much pressure but we'll see how it goes.

It's 23 degrees Celsius = 73.4 degrees Fahrenheit here in Sydney. Sun's out, I might go to the beach tomorrow if I get the day off work

Will keep the thread updated

[Rassy]

Somewhere I must have missed something, but how do you contact Keywin to order these gears? What is the price and shipping cost?

Thanks

Edit: Use the search, dummy:

ecrazyman@gmail.com

Okay, I'll sent Keywin an email

[voicecoils]

Somewhere I must have missed something, but how do you contact Keywin to order these gears? What is the price and shipping cost?

Thanks

Edit: Use the search, dummy:

ecrazyman@gmail.com

Okay, I'll sent Keywin an email

You'll have to ask him yourself, I don't know what he's asking from US buyers. I do know he only has samples at the moment.

[voicecoils]

A few more photos for those interested:

(I've had a closer look at the gears. Two of the 6 are quite badly cut with rough tooth faces and misshapen profile on one side. I'll try to get a pic soon)

[docnjoj]

The steel gear face profile would be a bit different than the nylon! The bearings may need running in! Dorothy may land in Kansas at any moment! Let us hope!
otherDoc

[docnjoj]

My metal gears from Keywin arrived today at work.

None of them spin smoothly. Varying degrees of 'lumpyness' when spun. Each have enough friction to stop almost as soon as my finger spins them around.

May have to look into pressing in new sealed bearings, not a complete deal breaker though

I'll pop them in tonight.

(crappy iphone picture)

Do U heat your gears and freezr the bearings or just put them in straight?
I have a different set I need to do, not Bafang!
otherDoc

[fechter]

I wouldn't worry too much about the bearing friction as the free spinning resistance is not a good indicator of resistance under load.

The gear tooth profile would worry me a bit more. I think if it is off by too much, it will make them very noisy. Should solve the stripping problem though.

[Reid Welch]

planetary spur gears. I started a new thread last night, not knowing then about this one.

In spur gearing, ALL of the load is carried by ONE tooth at a time.
Now, in the real world of newly installed gears, no matter how accurate the machining,
the spacing of the planet gear pinion posts is sooooo critical, that even C & C machining
cannot make the mere =three= gear teeth all shoulder their loads exactly the same:
in the new motor, ONE only, of the three plastic or metal teeth can shoulder the load.

Solutions: long, gentle, break in. The high points wear down quickly
Gear load then begins to "equalize" between the three.

Metal planets won't bust.
Soft nylon is NOT a suitable planet gear material for HD use.
Reinforced plastics, for just this purpose, have been manufactured since before 1920.
I believe Westinghouse was the first to introduce "silent" timing gears, for the intensely rough service
of replacing the noisy but bulletproof, cast iron, stock Model T half-speed (cam drive gear).

These gears were made of laminated layers of LINEN fabric, phenolic (bakelite) resin, impregnated,
intense pressure and then heat-cured. Nearly as strong as any metal, but noise-dampening, QUIET.

Eventually, in T service, even these gears, NOS or not, will fail. But T service of the non-metallic gear
is terrifically shock-y and the helical teeth (strongest form of gear tooth) eventually suffers fatigue.
One tooth bucks off, runs into the next tooth, snaps off that tooth: and your engine stops.

The new geared hub motors will get away from the use of non-reinforced "nylon".
They must!

And in any new geared hub motor: word to the wise: go very easy on it at first.
Because no matter how "perfectly" it is made, no way are all three gear teeth of the spur gears
gonna be carrying only one third of the total drive load; not until they've all "conformed" to local conditions.

Truth.

[TPA]

Truth.

Word!

[voicecoils]

I don't want to leave everyone without an update for too long

I've had the chance to replace the three nylon gears (it's actually a bit of a time consuming swap). Photos attached. The gears are solid little buggers. I've installed two of the well cut metal gears and took a file to one of the two gears with dodgy tooth cuts then installed it too. My circlips are starting to seriously bite the dust but I will look for some fresh ones soon.

I'll make a little youtube video of heavy metal bafang tomorrow (~18hrs from now). I ran it on my new truing stand today for a few seconds, it sounds a bit like a power drill now

[docnjoj]

Hey Reid! I agree with most of what you said, but in this case arent the planet gear loads shared between the sun and ring gears. Shouldnt this help longevity?
otherDoc

[voicecoils]

Regarding forces on this gear system, please see page 10 here:
http://www.asee.org/activities/organiza ... _paper.pdf

Two teeth / teeth roots of each planetary gear (at opposite ends) will bear the brunt of the forces. Similarly the posts the planetary gears are mounted on will experience a turning force on the post (what architects would call a cantilevered system).

[voicecoils]

For eyes and ears (videos as promised):
heavy metal bafang at 36v
heavy metal bafang at 72v

You may have to pause at the beginning and end of each to see the CA display. My point and shoot camera does not have the best autofocus.

Other bafang videos for audio comparison:
http://au.youtube.com/user/voicecoils

Cheers guys, can't wait to test it out on the road. It's dark already but I might make a night trip

[docnjoj]

The higher speed/voltage seems to get the noise range into a quieter zone! Thats similar to the nylon ones! Cant wait for mine to try just 1 steel!
otherDoc

[Reid Welch]

Just like fifteen million Model T's, metal gear-converted Bafangs: some will run like coffee mills and some will run rather quieter than that.

TIP: do as I did with my new eZee (plastic geared). FILL the housing partly with light motor oil (I used Mobil One SAE 20,
and ran for hours and hours, slowly enough to not churn the motor windings HARD with oil (which acts pretty ruff on windings and wire ties
at thousands of rpm).

Now, the eZee just happens to have a half dozen threaded hole, disk rotor mounts: perfect place to inject the temporary oil fill.

Presuming the Bafang has no such holes: you'd need to, while it's open, drill and tap the cover for a 6/32 (or other) small screw, to be your oil
fill-and-drain place. Make two such holes: one for fill and one for air-venting to allow drainage. Tip: one oil hol on the side, so you can drain whilst
the bike is laid on its side, and the other hole might be elsewhere.

Scenario: your newly metal geared Bafang. Install several ounces of light oil. Run unloaded for an hour.
DUMP the oil out into a clean, white plate. Look for metal sparklies (wear products of the new, soft, planet gears).

Refill and repeat. The noisy motor will run quieter, right off the bat (oil cushion).
With each run and drain, more sparkles (metal flake) will come out with the drainage.
Eventually, when the new planets are "worn in", metal generation will nearly cease.
The uneven "rrrr...rrrr...rrrrr" will eventually become more like a steady "rrrrrrrrrr" and softer in volume of sound.

Do not run the motor at super speeds with a full case of oil! That would be so hard on the windings, ties, and hall sensor mounts
...liquids at high speeds act almost like solids.

Instead, leave your Bafang nearly empty of oil when it is in actual service: an ounce or two at most,
or "none" at all (the teeth of the outer, ring gear will stay "wet",
and so, wet the planets.

And at intervals, to clean out all wear products, re-fill the motor with fresh oil, run slow, and then instantly dump the contents.
Look for the sparkles. They will generate for an indefinitely long time, I predict, but, as the involutes gradually self-machine (polish),
the metal generation rate will diminish greatly.

Do not run metal to metal gearing with mere "grease". It won't work well long term: high speeds, and the grease gets "pushed out of the way":
dry metal gears will gall and make a super mess of themselves, etc.

----
THIS IS AN EXPERIMENTAL TECHNIQUE. I CAN'T BE RESPONSIBLE FOR DISASTERS.
I HAVE NO PRACTICAL EXPERIENCE OTHER THAN WITH MY YET-UNUSED eZEE MOTOR.
YOUR RESULTS WILL VARY.

OIL IS THE FIRST CHOICE FOR GEAR LUBRICATION.
THINK: AUTO transmissions. AUTOMATIC TRANSMISSIONS: Other than for their need for special additives in ATF, due to their helical/sliding action teeth,
ATF -could work- for our need, EXCEPT that ATF may have a detergent, dissolution effect on any silicone-based Hall sensor adhesive.
THERE IS A RISK, that even plain, synthetic motor oil (or any motor oil) may, in time, de-anchor any glued-in Hall sensors. We don't know, not yet.

Oil oil oil. I know oil and break-in/wear in. Rrrrrrrr can become ummmmmmmm. That's our aim.
Be careful, take a risk, but don't blame me if you f anything in the doing of this new "new" trick: as old as gearing;] but new
to this new kind of hub motor.

Good luck must be made, not found like some lost penny.

r.