Ultimate lightweight wheel-motor concept

nice :)

are you already drawing on the case?
do you have a solution for the torque arm or clamping mechanism to the swingarm?


Punx0r said:
A free-wheeling crankset does sound good as it keeps the solution off-the-shelf? Simplifies the design of the motor side of things.

im afraid it will not work very well with a gearshift / chain tensioner and there will be more friction losses due to the always running chain.
it would be better to have a freewheel in the cassette or in the sprockets which are used.
 
madin88 said:
im afraid it will not work very well with a gearshift / chain tensioner and there will be more friction losses due to the always running chain. it would be better to have a freewheel in the cassette or in the sprockets which are used.
Extra losses from the running of an unloaded chain aren't worth thinking about. Surely, you'll be pedalling anyway, madin? :) You could broach the inner of an ENO Duo for a 2 speed driver freewheel but the smallest sprocket size will be 16t. I have a freewheeling crank with fixed rear sprockets on my eMoulton - it works fine.
 

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ok, if you say there will not be a problem than everything is fine :) i should not think that complicated lol
 
To be fair, if there are several options that don't require alteration of the motor design then fair enough :) Much like the gearing issue.

Miles, what size wheel is that in your latest rendering, please?
 
Looks great. Double bearings on the single support case are a must IMO. Never have seen a car stub with a single roller setup. All I have seen used have a inner / outer roller or a wide double row ball setup. On the seal, possible a labyrinth setup if you have a large flange hub or you can add a wide freewheel spoke guard type spacer with grease in between it and the back cover so they slip past each other without letting in debris.

On the pedal gearing, it may be possible to use a screw on freewheel adaptor and a narrow freewheel.
 
I agree long term slinky core makes the most sense to reduce scrap

I just dont think you can do it with hiperco50 which is super brittle

might be fun to run the sim with hiperco27 which is less brittle

even then I dont know if you could make slinky

27 has the same sat as 50 which is all you need if you have already determined we dont need super thin lams
 
The hiperco 50 and 27 look like amazing stuff. Found the physicals listed for the 50. http://www.edfagan.com/hiperco-50-coil.php Looks like it should be able to take some shaping at 9% elongation and at the relatively low hardness. Hard to say, with 49% cobalt what it acts like never playing with anything like it. The 27 is lighter and much lower stiffness also. Have not found it's elongation numbers yet.

Great download /paper on them both for stress and aging effects. They look very close electrically. https://www.google.com/url?sa=t&rct...HgPWadl-5muuPVDT5nDJwlw&bvm=bv.61965928,d.aWc
 
Ok. How about this for a plan?

I'll choose a slot/pole combination that can be scaled by a factor of 1.5.

The maximum diameter for 20" wheels was set by the need to avoid conflict with V brake mounts. If this diameter is multiplied by 1.5, it should be a good match for both 26" and 700c wheels.

I'll develop a prototype version for 20" wheels, as that's my interest and I can please myself...

Here, we can collectively work on the larger version which could be up to 500mm in diameter. Enough to satisfy even Luke...... :)
 
I like this approach just to test the concept. Better to start small, but......

If the small motor has similar performance to a mac/bmc but with better efficiency

most people would be happy or could just buy 2 ;)

Even the small motor is going to cost 2k USD to build a proto
 
Miles said:
Ok. How about this for a plan?

I'll choose a slot/pole combination that can be scaled by a factor of 1.5.

The maximum diameter for 20" wheels was set by the need to avoid conflict with V brake mounts. If this diameter is multiplied by 1.5, it should be a good match for both 26" and 700c wheels.

I'll develop a prototype version for 20" wheels, as that's my interest and I can please myself...

Here, we can collectively work on the larger version which could be up to 500mm in diameter. Enough to satisfy even Luke...... :)


Miles this is pure brilliance. :)
Parametric ebike motor size modeling.

Sign me up! It only takes cut files and I can have parts made. Ive got ready and capable vendor contacts for everything down to custom magnets. However, I think since it adds a lot of cost and hassles, optimizing for some widely available in bulk magnet that is available in high flux SH grades as off-the-shelf pieces.

I want to pay for your motors parts. I have a hunch your motors expensive parts will nest nicely inside my motors expensive parts on the laser cutting table. Im only going to do something like 10mm stator width though. If Im paying for hyperco, Im gonna use it's benefits. :) Folks not wanting it to be expensive can simply go 15mm wide or whatever works best, and it's still going to be more way more efficient/torquey than any other hubmotor near it's weight.
 
On the simulation miles you were getting torque estimates of around 25nm. Not sure if this will be enough for slow moving heavier load situations/hills without burning up relatively quickly. Folks with hub motor experience should have a better feel for this and can judge this better. If not we may want to keep it on the larger diameter side for general purpose, but also would like to see a smaller lighter version explored as weight is a critical factor here.

One thing that still is not clear to me on the controller side, is the electronic speed advance we could use for this to gain higher rpms and speeds. Dual controller profiles, harmonics, additional phases etc. Still mostly black magic to me. Just throwing that out for some input.

On the brittleness of the hiperco 50, I see now what the issues are with it. It work hardens tremendously. Rolling effects it electrically significantly also. Not sure they would work it in a completely annealed state. Thinking, any of the grain oriented types would most likely be grain oriented in the wrong direction for slinky construction regardless. Anyone have a feel of what is going on here in the strip forming stage of these types of metals. Interesting stuff.
 
speedmd said:
One thing that still is not clear to me on the controller side, is the electronic speed advance we could use for this to gain higher rpms and speeds. Dual controller profiles, harmonics, additional phases etc. Still mostly black magic to me. Just throwing that out for some input.

for more than 3 phases we need a special controller (like falco motors have). i do not know what the benefit would be by doing this (more torque?, higher efficiency at given output torque?).
dual controllers (2x 3 phase) would be a bit overkill for such a small motor..
using flux weakening / shift timing we can gain rpm. the question is how much can we gain to keep efficiency still good? i think about 10 - 20% should be doable.

with my adaptto controller im able to spin my cromotor to twice or three times the normal rpm (with the wheel off the ground).
yeah, the Adaptto Mini-E would be the optimal controller for this motor (if we not exceed the ERPM limit) :)
 
speedmd said:
On the simulation miles you were getting torque estimates of around 25nm. Not sure if this will be enough for slow moving heavier load situations/hills without burning up relatively quickly. Folks with hub motor experience should have a better feel for this and can judge this better. If not we may want to keep it on the larger diameter side for general purpose, but also would like to see a smaller lighter version explored as weight is a critical factor here.
I was simulating for 25Nm of torque....... I was getting about 85 Watts of heat at 25Nm. Would 30Nm continuous be enough?
 
Looking vary cool, I've wondered for a while if it wouldn't help speed development on several of the colborative ES projects such as miles motor designs and arlos's and zombiess controller development, if we ran a kick starter or more permissive crowd source campaign, to cover projected prototyping materials costs for a first run of product. this might be the perfect project to try this out on. If it works try it on the controller projects. Is there a way to gauge interest here by asking every one to check in on another thread at varying levels of future support?
(crowd source interest for new ES designed uber hubmotor)
Might look like this...The time has come! join the (E) voution, as part of the endless sphere research and development team. The members of the worlds largest community of zero emissions makers and enthusiasts need your help to move the cause of electric transport forward by collaboratively designing and producing a new design for a cutting edge bicycle electric hubmotor. (Insert cool video pitch, i.e. what's wrong with current product.. How ours will be better see peachy printer pitch .with your help we can make this happen. Debut to be at the first endless sphere a con to be held in sanfrancisco on .... (if my pretty pony fans have a gathering what's stopping us. http://bronycon.org

Suggested gifts at differing support levels.

1. (200) $20.00 endless sphere r and d skunkworks team member sticker set.. Join the (E) Volution
2.(200) $ 40.00 See 1. Plus 11x17 super hubby endlesphere exploded view cad drawing /art poster something like this http://srt8duster.com/wp-content/uploads/2012/07/heartbeatcity1.jpg
3.(100) $ 100.00See 2 plus poster signed by designer tec team members. plus animated endlesphere phone screen saver art of animated assembly cad file. and E.S. skunkworks team member tshirt
4. (50)$250.00 See 3 substitute bike jersey
5.(10) $2,000 Motor limited edition parts kit and 2 above
6. (5)$3,000 assembled motor and 3 above.
7. (3) $4,000 limited addition gold anodized numbered version signed by team members with special edition carbon fiber and magnet upgrades installed in your wheel.and 3 above.


Well what do you guys think?
 
Miles said:
speedmd said:
On the simulation miles you were getting torque estimates of around 25nm. Not sure if this will be enough for slow moving heavier load situations/hills without burning up relatively quickly. Folks with hub motor experience should have a better feel for this and can judge this better. If not we may want to keep it on the larger diameter side for general purpose, but also would like to see a smaller lighter version explored as weight is a critical factor here.
I was simulating for 25Nm of torque....... I was getting about 85 Watts of heat at 25Nm. Would 30Nm continuous be enough?

What do you think we can dissipate safely through the stator cover without venting. It is large but we should get a feel as to what levels will run away on us at slow / stop and go situations in warm weather. Say around 10mph /16kmhr average for ambient airflow. Where are the thermo guys in the group? Certainly the folks that will want more power can add cooling to them.
 
Can't seem to figure out how to move kick-starer post to new thread so it's not in the way here
 
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