An Advanced Friction Drive System

[AussieJester]

Welcome to the forum ThunderDuck ...

Of course you're right my apologies... welcome to the forum
not everyone here is an ass like me alot of the time haha

KiM

 

[deVries]

Could you share the model and vendor of the cheap outrunner? I am assuming that this motor has that extra bearing supporting the front of the bell.

Here's the link for anyone wanting to know all the specs on this cheap motor...

http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=5204

 

[EVTodd]

Keep in mind that the motor posted above isn't a huge outrunner with tons of power like a lot of people on this forum are looking for. The reason I'm using it is because my girlfriend doesn't weigh very much and she is only looking for an 18-20 mph top speed.

 

[deVries]

Sorry if I didnt get back to you on one of your questions a while back. I just must have missed it . I will try and answer the above for you but man, thats a lot of questions.

If you think that's "bad" -wait till you get into production AND on the tele-tubbies. :lol:

Better post a FAQ in your beginning first post of this thread. You can just edit in more info as you go along. Of course, you'll need a website too.

http://www.hobbyking.com/hobbyking/...NIGY_K-Force_120A-HV_OPTO_5-12S_Brushless_ESC

havent tried it so I cant comment.

This one, link above, is the "big brother" to the one you are testing now, so it should work too & maybe give more headroom on preventing the magic smoke.

Of course, let's hope that $60 dollar solution will not produce the magic smoke either.

 

[Kepler]

That ESC is physically too big for this drive. It needs to be less then 40mm wide. Keep in mind, this is not a high powered setup, its primarilly meant to be a hill assist. 1000W is plenty for hill assist and moves you along at a decent speed also. My rule of thumb with most RC controllers is to de rate them by about half expecially on the cheap Hobby City controllers. Stick to this rule and you will save yourself a lot of waisted time and money. I do push the the Castle Creations controllers closer to their rated capacity though.

 

[Kepler]

Keep in mind that the motor posted above isn't a huge outrunner with tons of power like a lot of people on this forum are looking for. The reason I'm using it is because my girlfriend doesn't weigh very much and she is only looking for an 18-20 mph top speed.

Definitely as small as I would dare go. Might not be suitable but good thing is both you and I are going to test it so we will know soon enough.

 

[deVries]

Keep in mind, this is not a high powered setup, its primarilly meant to be a hill assist. 1000W is plenty for hill assist and moves you along at a decent speed also.

If you can get the standard kit to 20mph on the flats, then that will be the perfect speed for USA. Macho users can just bump the voltage to go faster as long as you allow for wiggle room in your (programmable?) throttle/controller setup... maybe 28mph before having to upgrade the throttle/controller setup???

Can you set it up close to this "ideal" ?

 

[morganw]

My apologies for removing the detailed drawings. Things have really snowballed here and it’s gone from a hobby project to perhaps something much bigger.

I understand completely. I'm going to try to build a similar design for a monotube SWB recumbent, but I'll still buy one of yours (I'm watching for your "ready to take orders" post ) for a diamond frame.

You have all the information you need to copy this for your own use. Make one out of wood first. I recommend particle board to finalise dimensions.

You're right. The photos from all angles are very helpful. I think I'll build a fit-only non-functional version out of hardboard first. It'll be strong enough to see if I can make the torque-swing work but not enough to actually drive a wheel. I doubt that I'll make the swing work, but it sure would be nicer than having to use a shifter cable to engage.

 

[vancblue]

A WONDERFUL CONCEPT & DESIGN.

Naming: Maybe avoid the term 'friction' and call it "Kepler Bike Booster System" because that is exactly what it is!

. . . and yes, please set a couple (or more) aside for me


This product would also circumvent the restrictions in some parts of the world on not being able to take an electrified bike on public transit because of the weight restrictions of the motor and batteries.

 

[Kepler]

Managed to finally get some testing in between rain show down here in sunny Melbourne Oz. With the little Turnigy 55-60D installed, went out to see if I could burn this little sucker out. Running a 5S 5000 pack, I pushed the little motor as hard as I could with lots full throttle uphill climbs, accelerating from low speed to full, and everything else in between. Performance was mild as expected but acceptable and felt similar to my 408 hub motor on 36V. Didn’t give the motor any real break and finished the pack off right down to the LVC.

Quickly back into the workshop to test motor and esc temperatures thinking this is not going to be good, in fact I didn’t dare put my hand on the motor. Using a Fluke infrared heat gun, I measured the temperature of the motor and couldn’t believe the readings. Took readings all over the motor and to my surprise, the highest reading I could get was only 30 deg C. That’s 86 F for our US buddies Sure enough, the motor felt only slightly warm by hand. ESC was nice and cool also. Unfortunately I didn’t have an amp meter fitted at the time but its fairly obvious this motor isn’t pulling a lot of amps even under load at full throttle.

So preliminary testing with this entry level motor is very promising. On 5S, speed was around 25kph and as a hill assist, power was adequate for the job. Best of all, the motor and ESC didn’t seem stressed at all which was a very pleasing result. Of course this is just a preliminary test and obviously more testing is required but this is a very promising result. As this is a low power config, I think that the 85A K-Force will be up to challenge so for a about $70.00 we may well have a viable motor ESC combo for the drive.

I will run another pack through the setup tomorrow and also try a 6S setup to see how the motor handles the extra voltage.

On another note, I am close to sorting out the pivot dampening issue with engagement now super slick. The engagement is so smooth now, you can hardly feel the motor take up on the tire especially with the low power setup. Things are looking good. I'm excited!!

 

[tritonwow]

I'm excited!!

+1
Fantastic work Kepler and thanks for sharing the buildup. You might just be able to quit your day job sooner than expected!
I'm just trying to figure out how I'm gonna arrange it with my Thudbuster (might have to forego a bit of comfort as I've come to like that device.)

 

[zap]

Didn’t give the motor any real break and finished the pack off right down to the LVC.

Any estimate on total distance on that ride?

It's been a treat following along on you're progress.

 

[EVTodd]

Managed to finally get some testing in between rain show down here in sunny Melbourne Oz. With the little Turnigy 55-60D installed, went out to see if I could burn this little sucker out. Running a 5S 5000 pack, I pushed the little motor as hard as I could with lots full throttle uphill climbs, accelerating from low speed to full, and everything else in between. Performance was mild as expected but acceptable and felt similar to my 408 hub motor on 36V. Didn’t give the motor any real break and finished the pack off right down to the LVC.

I'm glad to hear positive news about the motor. I'm still waiting for mine ... Did you have to add any extra glue to the magnets? I've been reading quite a bit about the company gluing the heck out of them from the factory now so I'm hoping to just slap it on a drive and go.

I'm also interested in the range since this is exactly the setup (battery and motor) that's going on my girlfriend's bike. I think she's going to be happy with the weight difference between 24v 7ah of lead (doesn't sound like much but she got around 15 miles of assist, we pedal a lot) and a kollmorgen motor vs a tiny outrunner with lipo.

 

[Kepler]

The motor completely un modified and has done a bit of work prior to this on a kick scootor that I setup for my kids. I want to test this as a stock motor and see what lets go. I think a manditory bearing replacement and perhaps running some thin superglue between the magnets might we a worthwhile exersize for people who choose t go down this path.

Distance wise, this was not an indurance test so can't give any solid numbers. I was out for about 30 minutes during this test and did very little peddling so I think I would have covered around 10kms.

 

[Kepler]

A quick update.

Refinement has been the main focus this week. Fitted new side plates and pivot plates in black Acrylic instead of aluminium. The Acrylic plate is surprisingly strong especially when used in a box construction like this. So far this material is looking quite suitable for certain parts of the drive and in conjunction with the 60-65D motor, weight is down to 1200 grams. The black acrylic I think looks really neat and providing it survives testing, will most likely become a standard feature.

The drive dampening method has been refined and I am now satisfied with the action. This has added another 5 parts to the drive but well worth the added complexity considering wet road operation is now covered together with silky smooth take-up during acceleration.

Tested 6S with the 55-65D motor. Not impressed. Power increase was marginal and the motor temp was unacceptably high after the ride. 5S is a better fit for this motor. Power is gentle but adequate on 5S and I can confirm 25kph on flat ground no peddling. I believe this is still an acceptable entry level combination. I will try and post some video of my official test pilot (11 year old daughter) putting the 60-65D equipped drive through its paces in the next day or two.

For those hanging out for final pricing, I am close to tying this down but still waiting on a few quotes to come in. Initial sales will be based on drive only without any electronics as these sales will be mainly to forum members who are more then capable of adding their own motor ESC combo. I will of course be proving recommendations in relation to running gear. The drive will be offered both built and in kit form with kit form being the most economical purchase.

The controller interface is a few weeks off yet but will be well worth waiting for. This piece of electronics will tie the whole project together with features never offered before within the ebike industry.

Getting this drive to market has been a huge undertaking but its nice to see light at the end of the tunnel. The detail required to actually drag it all together has been mind boggling and there is still plenty of work to go. However I am getting there and very excited to be at the pointy end.

A couple of photos of the drive as it approaches production stage.

 

[AussieJester]

A couple of photos of the drive as it approaches production stage.

Just keeps getting better IMO.. Can you give a 'ball park'
figure for the kits mate? Would 250-350 (no electronics) been in the general area? Anywayz, again nice work mate...You have me thinking of doing a "direct drive" setup myself on a small Huffy Slider trike i am kitting out for mates youngin, the drive however will need to be on the front wheel l-)

Look forward to looksee at the finalised production unit...

KiM

p.s will you please include a ride and up close video of the drive in action to ?

 

[Kepler]

Thats the price range I am shooting for. Need to have parts made in lots of 50 though to meet that target so its a big commitment.

Jester building a friction drive, now we have heard it all. Next thing the we will see the cruiser with a friction drive hanging off the back.

 

[deVries]

Refinement has been the main focus this week. Fitted new side plates and pivot plates in black Acrylic instead of aluminium. The Acrylic plate is surprisingly strong especially when used in a box construction like this. So far this material is looking quite suitable for certain parts of the drive and in conjunction with the 60-65D motor, weight is down to 1200 grams. The black acrylic I think looks really neat and providing it survives testing, will most likely become a standard feature.

By Acrylic, exactly what material do you mean? Plexiglass? (methyl methacrylate) or Lexan? or ?

The controller interface is a few weeks off yet but will be well worth waiting for. This piece of electronics will tie the whole project together with features never offered before within the ebike industry.

This interface might be helpful for other RC motor users on ES. It can probably be applied to other direct drive rollers (i.e. EVTodd) on the tire too? Can you offer this interface to ES members with RC motor applications? Did someone on ES help you develop this option?


8)

 

[AussieJester]

Jester building a friction drive, now we have heard it all. Next thing the we will see the cruiser with a friction drive hanging off the back.

haha ..nay that would be pushing things a lil far :lol: if i did though it would be a knock off of yours Kepler...perhaps i can carry it ina back pack as a back up...:: slaps face :: :: shakes head :: i mean i will be making my non frock setup bullet proof

All the best getting it into production without any major hiccups...
I been suggesting the drive to a few people couple of my mates i showed it too are very interested so chances are better than good ill have one of the Kepler drives to fit to a bike!

KiM

 

[EVTodd]

I'm a little surprised by the acrylic pieces. Around here any plastic stock usually costs more than aluminum. Are you doing it for weight savings or material cost? It can't be for the strength can it?

Keep in mind that many plastics deteriorate when exposed to uv for a long time. It may not be a huge issue but it may since those pieces are a pretty important part of the drive.

 

[Kepler]

Refinement has been the main focus this week. Fitted new side plates and pivot plates in black Acrylic instead of aluminium. The Acrylic plate is surprisingly strong especially when used in a box construction like this. So far this material is looking quite suitable for certain parts of the drive and in conjunction with the 60-65D motor, weight is down to 1200 grams. The black acrylic I think looks really neat and providing it survives testing, will most likely become a standard feature.

By Acrylic, exactly what material do you mean? Plexiglass? (methyl methacrylate) or Lexan? or ?

The controller interface is a few weeks off yet but will be well worth waiting for. This piece of electronics will tie the whole project together with features never offered before within the ebike industry.

This interface might be helpful for other RC motor users on ES. It can probably be applied to other direct drive rollers (i.e. EVTodd) on the tire too? Can you offer this interface to ES members with RC motor applications? Did someone on ES help you develop this option?


8)

The acrylic material is methyl methacrylate. In relation to the interface, I see no reason why it cant be sold as separate unit. And yes, someone else is developing the interface basically to my specification.

 

[maydaverave]

Very cool tec.

 

[Kepler]

I'm a little surprised by the acrylic pieces. Around here any plastic stock usually costs more than aluminum. Are you doing it for weight savings or material cost? It can't be for the strength can it?

Keep in mind that many plastics deteriorate when exposed to uv for a long time. It may not be a huge issue but it may since those pieces are a pretty important part of the drive.

Yes, 1200 x 2400 sheet is twice the price of Aluminium however laser cutting cost is reduced by about half. Other advantage is that you save on anodizing further reducing costs. The finish on the acrylic looks really neat and it is UV stablized.

That being said, although quite strong, you may break a side frame or pivot plate if the drive was dropped from height. However, I think its plenty strong enough for normal operation. I pick a Scorpion motor tomomow and plan to run this motor hard on 6S with the Acrylic parts. This will be a 2000W setup so it should test out the strength of the Acrylic under the highest recommended load.

Interested to know what the general consensus is in relation to Aluminium versus Acrylic versus Carbon Fibre. Cost wise, I estimate anodized aluminium will add 10% to the price over Acrylic with Carbon Fibre adding around 20% to the drive kit over Acrylic. Are people willing to pay the extra for the bling or is cost the biggest driving factor?

 

[AussieJester]

Interested to know what the general consensus is in relation to Aluminium versus Acrylic versus Carbon Fibre. Cost wise, I estimate anodized aluminium will add 10% to the price over Acrylic with Carbon Fibre adding around 20% to the drive kit over Acrylic. Are people willing to pay the extra for the bling or is cost the biggest driving factor?

I have used a far whack of acrylic when i was heavily into pc case modding and making my own watercooling componets for the PC.
Generally people don't take to acrylic like they do to aluminium and particulalry carbon fiber, alot see it as 'cheap' and inferior
in comparison to the two alternatives. Personally i love the stuff. If you ever want to join acrylic i can HIGHLY recommend
Acrifix 191 and Weldon Cements have used both they are fantastic products for cementing acrylics together, once
set thats it they ain't coming apart without breakage.

KiM

 

[deVries]

That being said, although quite strong, you may break a side frame or pivot plate if the drive was dropped from height. However, I think its plenty strong enough for normal operation. I pick a Scorpion motor tomomow and plan to run this motor hard on 6S with the Acrylic parts. This will be a 2000W setup so it should test out the strength of the Acrylic under the highest recommended load.

Interested to know what the general consensus is in relation to Aluminium versus Acrylic versus Carbon Fibre. Cost wise, I estimate anodized aluminium will add 10% to the price over Acrylic with Carbon Fibre adding around 20% to the drive kit over Acrylic. Are people willing to pay the extra for the bling or is cost the biggest driving factor?

I have a significant background in plastics, and I would strongly suggest not using MM. It is prone to crazing and then cracking along hairline scratches/stresses AND drill holes! Polycarbonate or Lexan tm is the only choice I know of that would not tend to craze and crack. I'm sure there are other plastics that could be used too, but these may be more expensive.

To be honest, I would only buy a kit with Lexan/PC or aluminum (my preference) or some other material besides Methyl Methacrylate. :wink: