An Advanced Friction Drive System

[Kepler]

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. To be honest those original drawings were based on a drive specific for my very tall disc brake equipped hardtail mountain bike and as such many of the dimensions were not going to suit the vast majority of bikes out there. I felt a direct copy of that layout would frustrate quite a few people if they couldn’t adapt it to their bike satisfactorily.

Hence the reason why the Mk3 drive is now under development. As I have previously mentioned, this drive will fit most bikes and has a number of enhancements over the Mk2 version. In addition to the drive, I am co developing a very compact PIC micro controller based RC speed controller interface about the same size of an RC ESC that will allow the connection of Hall based throttles and will also incorporate a wheel speed sensor which is designed to only allow the drive to start when the bike is above a set minimum speed. This solves a number of issues like over straining small RC motors when starting from a dead stop or possible tire damage due to slippage on start-up. It also has the added benefit of getting around most sync issues as the motor wont be trying to start from a dead stop. My testing has found it only takes around 5mph to get over these issues. Other features will be ebrake and pedal assist inputs with lots of nice future enhancements including the addition of current limiting and the possibility of a wireless displays. Lots on the drawing board at the moment.

So back to the drive. As Jester says, a patent on this type thing is a waste of time. Too easy to make a small change and copy from there. So the solution is to say copy to your hearts content but then make the drive so accessible and well priced that it’s just not worth your time an effort to go down that path when someone else has already done the hard work and basically sorted out all the bugs. It takes me about 30 hours to hand build a drive of this standard even without chasing around for all the components and materials.

The Mk3 drive is CNC ready and will be offered up as a pre built unit for those who want that but also offered as a kit that requires straight forward assembly and the addition of your choice of motor and ESC. I will be recommending the best suited ESC/Motor combination but people can still make their own choices if they wish. The business plan will be to keep the margins low and the sales volume high. That way everyone wins. The drive in kit form can then be flat packed for shipping further reducing costs.

Another piece of good news is that it looks like the drive has been accepted on an Australian National television show called the New Inventors so I might even get 5 minutes of fame on the teli.

Down side here is that getting a project like this ready for manufacture takes much time effort and investment. I am working as hard as I can to get this out and will have the Mk3 prototype ready to show by the end of the week. However, I see at least another 4 to 6 weeks before drives are ready for sale. I think it will be well worth wait though and hopefully be a drive even the diehard power junkies might want to own as a second drive perhaps for the wife’s bike.

 

[deVries]

In addition to the drive, I am co developing a very compact PIC micro controller based RC speed controller interface about the same size of an RC ESC that will allow the connection of Hall based throttles and will also incorporate a wheel speed sensor which is designed to only allow the drive to start when the bike is above a set minimum speed.

Co-developing -another ES member by chance?

I think it's fantastic you might have something ready in kit form with 4-6 weeks.

Thanks for the update & look forward to the MK3 preview later this week or next...


8)

 

[zap]

Other features will be ebrake and pedal assist inputs

I think this drive would be perfect for a pedelec. I never did like the idea but I recently got a chance to ride a Kalkhoff Pro Connect... what a nice ride.

Good luck with the business Kepler!

 

[EVTodd]

Kepler,

It's cool to see you taking your drive to production. Over the past few months I have thought about doing the same with my drive but my fear of regulations and liability has stopped me (keep in mind that I'm a bit ocd. lol). Are you planning on keeping within the wattage limits of each country you sell your drive in? Is that even an issue? Is it just a matter of saying "I'm selling a kit and what you do with it is your problem"?

I know Recumpence (Matt) and several other companies sell mega watt drives but I also know that the "for use off-road only" thing doesn't hold any water here in the states. Am I just being paranoid?

 

[AussieJester]

Is it just a matter of saying "I'm selling a kit and what you do with it is your problem"?

Thats the stand i would be taking, i would also print a little label for the packaging and the drive itself that reads
along the lines of "Not for use on public roads" Then its up to the buyer as to where he rides it ain't it?
Austrlia has no law like the USofA that outlines the legalities of mass produced bikes such as the USA federal law does.
So its not ilegal to sell the bikes, nobody stocks in ecessof 200watt bikes simnply because majority prolly wouldnt buy them.
I think a drive unit at the right price would sell besides, i think most of the sales would be from outside of OZ anywayz wouldn't they? I know ill be recommending the Kepler drive when its available for noobies after a "direct drive" rc setup.

KiM

 

[EVTodd]

Is it just a matter of saying "I'm selling a kit and what you do with it is your problem"?

Thats the stand i would be taking, i would also print a little label for the packaging and the drive itself that reads
along the lines of "Not for use on public roads" Then its up to the buyer as to where he rides it ain't it?
Austrlia has no law like the USofA that outlines the legalities of mass produced bikes such as the USA federal law does.
So its not ilegal to sell the bikes, nobody stocks in ecessof 200watt bikes simnply because majority prolly wouldnt buy them.
I think a drive unit at the right price would sell besides, i think most of the sales would be from outside of OZ anywayz wouldn't they? I know ill be recommending the Kepler drive when its available for noobies after a "direct drive" rc setup.

KiM

I would probably recommend Kepler's drive too, I still think it needs a knurled sleeve around the motor and a bit smoother transition to the tire but I'm sure that's being worked on. I totally commend him for having the stones to bring it to production. Like I said, I'm a bit on the paranoid side when it comes to producing bike parts. Keep in mind that I was involved in the BMX industry for quite a while and am a bit familiar with some of the goofy regulations that go along with bikes here in the states. Then again, I know a guy that's a multi-millionaire from that industry and it seems like he kind of ignores all of those regulations.

 

[Kepler]

The fact that its a kit gets around most of the legislation issues and is one of the main reasons for going down that path. In relation to built drives, if they are to be sold comercially, then they need to comply to a specific countrie's regulations. This is why the controller is PIC based and will be ebrake and pedal assist ready. The PIC uses a removable chip so its just a simple matter of fitting the correct chip for the region. A non public road chip could then be purchased for those who want it.

In relation to the knurled sleeve, you are right Todd that it needs to be considered. The non sleeved motor works fine in the dry but we all dont live in low rainfall areas like us in OZ. Its definitely in the pipeline together with a simple stick on abrasive that I need to test.

Still cant decide if the wording of the max power legistlation is 200W input to the motor, 200W output from the motor or 200W at the wheels. I have tested a few so called legal ebikes here and found that they were more like 500 to 600W input.

 

[Miles]

Still cant decide if the wording of the max power legistlation is 200W input to the motor, 200W output from the motor or 200W at the wheels.

I thought it was 200 Watts peak output at the motor shaft?

Did you see this: http://www.endless-sphere.com/forums/viewtopic.php?p=263415#p263415

 

[AussieJester]

^^^ tiz what Miles says i believe....new law that was talked about was going to be 250watt specifically outlined 'at the rear wheel'

Have you thought of some form of heavy duty coating to the can of the motor Kepler e.g epoxy and sand/brit/glass etc etc etc mix

KiM

 

[Kepler]

Havent really considered that idea. maybe just coat the can in a thin layer of epoxy and roll it through some sand. Is that what you are thinking?

 

[bandaro]

go to a hardware store and get the grip nosing covering for wooden steps. we use the stuff at work, comes in rolls like a tape, is super sticky and has grit in it, so your feet grip onto it on the steps, would work brilliantly. the stuff lasts on the steps for over 25 years as well.

 

[Kepler]

Nice idea. Well worth trying. Going straight to Bunnings this morning to get some to test.

 

[spinningmagnets]

Perhaps sell it in kit form as a wheel-barrow/mobility-scooter power-assist unit. If somebody puts it on a bicycle, thats not your fault.

 

[Kepler]

I would probably recommend Kepler's drive too, I still think it needs a knurled sleeve around the motor and a bit smoother transition to the tire but I'm sure that's being worked on. I totally commend him for having the stones to bring it to production. Like I said, I'm a bit on the paranoid side when it comes to producing bike parts. Keep in mind that I was involved in the BMX industry for quite a while and am a bit familiar with some of the goofy regulations that go along with bikes here in the states. Then again, I know a guy that's a multi-millionaire from that industry and it seems like he kind of ignores all of those regulations.

Appriciate the support and input Todd. If the above suggestion works well and i dont need to go to a knurled sleeve, this could be a cheap and simple solution. The Mk3 drive has a smoother transition to the tire also by incorporating a simple dampening system. Hopefully all bases are covered

 

[Kepler]

Perhaps sell it in kit form as a wheel-barrow/mobility-scooter power-assist unit. If somebody puts it on a bicycle, thats not your fault.

Actually, a wheel barrow assist, wheel chair assist, pram asssist, golf buggy assist are all being tossed around at the moment using the same design principles.

I think in kit form in conjuction with the correct documentation, I am quite well covered. Built drives will simply haveto comply. (optional power chip available of course )

 

[AussieJester]

Havent really considered that idea. maybe just coat the can in a thin layer of epoxy and roll it through some sand. Is that what you are thinking?

Yup, I would try this using the same industrial strength epoxy i used to make the teeth on my rear pulley
Would be dead simple to do and possible last longer than sticking on adhesive coated strip? Would need to rough a inch or so wide strip
up on the motor can first obviously....

KiM

 

[Kepler]

Progress on the Mk3 drive continues and is currently being tested for compatibility on a number different bikes. The drive has been fitted and tested on a few different sized mountain bikes and is a very straightforward installation on this platform. I have also fitted the drive to my 11 year old son's BMX bike. This was quite straightforward to fit also and goes really well. Set on around 1000 Watts, this small bike really scoots along and is a heap of fun to ride. I will be fitting the drive on a high end road bike tomorrow so that should be interesting but I don’t foresee any issues. It will be interesting how the 23mm high pressure tire handles the roller though.

So what’s new.

Obviously the seat post mounting system. It’s not quick release in its current form but only takes a couple of minutes to fit. I opted for the rigidity of the billet clamp rather then the pack rack style clamp. This may change in the future but I needed to stick with what I can easily manufacture at this point.

To cater for different sized bikes, the clamp is designed to accept different sized spacers to adjust the distance of the drive from the seat post. The drive follows the seat post angle and as such increasing the distance the drive is from the seat post also moves it closer to the tire. This in conjunction with moving the clamp up and down on the seat post opens up a huge range of bikes that can accept the drive. Also the seat post clamp is designed to fit the 3 main seat post sizes and uses removable sleaves to achieve this.

The drive is sightly bigger then the Mk2 drive and has larger areas to install electronics giving people more options in relation to types of controllers. That being said, its still designed for RC style ESCs. The upper top plate is designed to act as an extended heat sink for the ESC and doubles as an adjustable clamp to hold the ESC in place.

Overall, the parts count has been reduced and materials sizes selected that are off the self rather then every dimension being custom machined.

The pivot stop has been improved with the original cable stop now deleted.

Improvements have been made to electronic compartment's water proof ness.

Items still being worked on are:

Improving the roller grip. The non slip tape is being tested at the moment and seems to be quite effective. I have run it for about 10km so far and it is showing no wear at all and sticks really well to the can. Grip is much improved and now works in the wet without any signs of slipping at all so this is a good step forward.

It does have a downside though. As this drive relies on the motor assembly feely pivoting, the extra grip causes the motor to constantly bounce off the tire when coasting. I am working around this at the moment by introducing a dampening system to the motor pivot. Adds a bit complexity but I think its worth introducing for the sake of being wet weather capable.

So as you can see, the drive is close. 3D modelling is complete and 2D shop files are ready to be sent the laser cutters and CNC machinists for manufacture. The Throttle interface is still about 4 weeks off but this doesn’t stop me getting mechanical assemblies started. Hope to have some pricing available in a week or 2.

 

[deVries]

So what’s new.

Obviously the seat post mounting system. It’s not quick release in its current form but only takes a couple of minutes to fit.

1) Excellent progress. How much (total) weight is added compared to the original mount?

The drive is sightly bigger then the Mk2 drive and has larger areas to install electronics giving people more options in relation to types of controllers. That being said, its still designed for RC style ESCs. The upper top plate is designed to act as an extended heat sink for the ESC and doubles as an adjustable clamp to hold the ESC in place.

What is the battery compartment dimensions & ESC mounting dimensions?

It does have a downside though. As this drive relies on the motor assembly feely pivoting, the extra grip causes the motor to constantly bounce off the tire when coasting. I am working around this at the moment by introducing a dampening system to the motor pivot. Adds a bit complexity but I think its worth introducing for the sake of being wet weather capable.

2) Is the drive/motor going to be able to lift off the tire and not bounce with the dampening system when the throttle is off?

3) What size motors length/diameter can be used?

Hope to have some pricing available in a week or 2.

8)

 

[spinningmagnets]

Absolutely brilliant! good job. Not that you need any inspiration, but there's an excellent article on the man who started the "leatherman" multi-tool in Popular Mechanics magazine. He was using a Swiss army knife on a repair job, and wished it had a pair of pliers in it. The prototypes he made were originally out of wood and aluminum (just for show) because he was changing and improving them so rapidly.

He tried to get 5 big tool companies to make and sell it, and they were all uninterested. He finally got a company to license it, and the rest is history. A dozen companies are now making similar fold-up multi-tools. Its literally a global billion-dollar industry.

In the 1970's many in industry laughed at the idea that anyone would want a "home" computer, and in the 1980's the big bicycle manufacturers thought mountain bikes were a passing fad, and would remain a tiny niche market not worth investing in.

When Gasoline hits $5/gallon (see: Gulf oil spill/instability in the middle-east), you will have more business than you can handle...

 

[spinningmagnets]

"...It’s not quick release in its current form but only takes a couple of minutes to fit..."

Seat posts are easy to remove, and bring inside, so the seats won't be stolen (and to make a stolen bike attempt less rideable). College students aften remove saddles from locked up bikes.

 

[tritonwow]

Progress on the Mk3 drive continues ... Hope to have some pricing available in a week or 2.

Subscibed (should have done this months ago) AND
put me down for two kits.

I want to get my father back on a bicycle for exercise and his biggest excuse is the small hills he has around his house.

Who could pass up one of these babies?

Triton

 

[ThunderDuck]

Gday Kepler ...

You are probably already aware of the "Friction Drive" subforum over at
motoredbikes.com ... I would imagine its your best source of information
on wet weather friction roller slippage (and attempts to overcome) and wear.

My understanding of the collective wisdom ;
* Friction drives are essentially a dry weather beast ...
* Wood, polurethane, rubber rollers all met with only limited success in the wet.
* A knurled hardened steel roller will wear surprisingly quickly when exposed to
sand and road grit ... the idea of a replacable sleeve over the motor seems appropriate.

I'm semi retired and would love to fit your drive to a Dahon Folder to accompany me
on overseas trips ... Will be following its development with great interest,

Drew.

 

[Kepler]

1) Excellent progress. How much (total) weight is added compared to the original mount?

About 200 grams but the production clamp should be around 50 grams lighter

What is the battery compartment dimensions & ESC mounting dimensions?

Top compartment is 100mm x 40mm with the lop plate designed for speed controllers 16mm high to 22mm high. The bottom section is 75mm x 40mm x 35mm high

2) Is the drive/motor going to be able to lift off the tire and not bounce with the dampening system when the throttle is off?

3) What size motors length/diameter can be used?

Yes the motor still will swing away from the tire when coasting.

The drive is built for 48mm diam motors and currently suits the Hyperion 4045 series of motors and Scorpion 4035 motors

 

[Kepler]

Absolutely brilliant! good job. Not that you need any inspiration, but there's an excellent article on the man who started the "leatherman" multi-tool in Popular Mechanics magazine. He was using a Swiss army knife on a repair job, and wished it had a pair of pliers in it. The prototypes he made were originally out of wood and aluminum (just for show) because he was changing and improving them so rapidly.

When Gasoline hits $5/gallon (see: Gulf oil spill/instability in the middle-east), you will have more business than you can handle...

Thanks Spinningmagnets. You just never know where things might take you. Will give this my best shot and see where it takes me.

In regards to removing the seat post with the drive attached, makes sense. I see the rigidity of the billet clamp as a very positive feature.

 

[Kepler]

Progress on the Mk3 drive continues ... Hope to have some pricing available in a week or 2.

Subscibed (should have done this months ago) AND
put me down for two kits.

I want to get my father back on a bicycle for exercise and his biggest excuse is the small hills he has around his house.

Who could pass up one of these babies?

Triton

Glad to hear you are on board. Cheers Triton