Project Velobration: The Common Power Module

MattyCiii

100 kW
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OK, the name is a little queer. "Velobration" is a portmanteau of "velomobile" and "collaboration". It's the name I'm using for now to label an effort by 900steve and I to build a common platform we each can use as a foundation for our respective next builds.

The Concept: Design and build a mid drive "box" optimized for the purpose: to be an excellent electric/human power plant. Once built, build a bike around it. It will physically bounded as follows: It will be aft of the top tube and the down tube. It will be below the seat. The rear wheel will be suspended. The common power module will be what the rear suspension pivot and shock mate with. Look at this thread to get a mental picture...
--- I look at the GNG drive, or Stokemonkey, or the latest generation European mid drives like the Bosh system, and what I see is a design philosophy of Start with a bike, then modify it....
Bullshit! I say, start with a drive system, and then figure out how to build a bike around it.

Outline: Steve and I have a common baseline. The sum total of his and my electric bike experience are riding my bikes - insanely responsive RC drives, NuVinci pedal power for smooth shifting human input, etc. After lots of scratch drawings in CAD and on graph paper, we decided there's merit to building a common power module that houses the following:

1. Human powered pedal cranks, and possibly use an ATS or Schlumpf drive for greater gear range,

2. RC motor and reduction. Look at my Dahon Folding Bike. Motor and reduction are pretty close to the center of the bike which is nice. Center the mass, it's good for snappy performance.

3. Combine power centrally, using a jack shaft. Consistent with one of the fundamental constraints of my third bike build (keep weight and complexity away from the wheels), we'll combine motor and pedal power in the common power module by way of a jackshaft.
--- Moreover, we've decided to use a NuVinci N360 as the jackshaft, and to use the axle of that NuVinci as the pivot point for the rear shock. This ties up a lot of little issues into a neat little package. But this creates a design-packaging nightmare and requires lots of thought, and more than a few custom parts. But that is what engineering is all about - compromise, and finding solutions.

We've started the design/build of this common power module (CPM). Once we've worked the bugs out there will be multiple CPMs - Between Steve and I we'll build at least 4, maybe more depending on economies of scale (for example if we outsource anything to Big Blue Saw, they have a giant price break when ordering 5x versus ordering 4x...). Steve and I will start posting comments and pix to illustrate the build. Then as we go from the common foundation to full bike build, we'll each have our own design goals and needs, and likely have radically different complete bikes (for example I want my bike to be a folder but that's not necessarily high on Steve's list.

Stay tuned, this is going to be interesting...
 
This project is still in its infancy, so there's a lot of talk. Ideas tossed around, quick CAD and graph paper designs - then re-designs. It's the "vapor ware" phase of the project where there's a lot of talk and not much in the way of "stuff". But, we have our first stuff.

Using an NuVinci N360 jackshaft and the pivot point for the rear suspension is a challenge. The N360 is built for 135mm dropouts. If you stack 6mm plate x 2 sides onto that (to fix the N360), plus nuts, etc., you're too wide and get heel strike. So, the jackshaft has to be far enough behind the cranks to compensate.

Thus, we're starting with the N360, and designing the Common Power Module (CPM) outward from there. Right now all we have is thus:
1. The N360, mounted in a temporary fixture.
2. A 30 tooth chainring, with the 5 chainring bolt mounts milled off and 18 x 3mm holes drilled such that the chainring can bolt to the right side flange of the NuVinci. The purpose of this chainring is to host the chain that drives the rear wheel sprocket in the finished bike. This is a compromise part: Chainrings wear - so it would have been best to find a way to use a completely standard off the shelf component. But that was not possible, so we went with an off the shelf part and did some custom processing to it in the form of the 18 bolt holes and removal of the 130mm BCD mounts.

In the coming days/weeks, we're building a plywood frame to mount the jackshaft and pedal cranks into. Steve is real skilled with CAD - this is not just going to be swags & cut twice/measure once hacking. But unless you're really good with CAD, there's nothing like mounting real parts into a frame that places parts in real 3 dimensional space. So, that's what's next.
 
I am very interested in this, I have been wanting/planning to build a full suspension dh mountain bike with a nv171 as the jack shaft and an 80/100 as the power source (I need to start my build thread). The big issue is the width, and getting it to fit between the cranks. I'm going to cut mine down as narrow as I can, I'm shooting for 6.5" total width. Then put it just outside the pedal circle (above). That gets me an extra 1/2" of width per side and just clears my feet! It'll be tight. I'm probably going to put the output sprocket on the left side, but then that creates a problem at the rear wheel (custom parts)....I'm using the n171 so I can put 2 input sprockets on it. I can't see how that'll fit an n360.

Wait!
Is the motor power going thru the Nuvinci? I want my bike to climb mountains, so it seems having the lower gearing is the way to go.
 
Electric drive to NuVinci will be supplied to its left side at the jackshaft (using an implementation of my vaporware NuVinci Left Side Freewheel design). So no, the electric drive will not see any mechanical advantage of the gearing.

Why?
1) This design is complex enough already! I would pretty much need a second jackshaft to combine human and electric power to the NuVinci input if I wanted to run both through the gears.
2) I've proven on my other builds that driving the bike with a fixed RC drive reduction gives me plenty of torque for the lower 5/6th of the total range of speed. I get "unintentional wheelie" power from 0-15mph while still having plenty of hustle right up to top speed of ~33mph. I'm comfortable & happy with that.

I have a drawing I'll post up in the next few days to illustrate. But basically the N360 will get human power input at its freewheeling cog (where it normally gets power in), will get electric power on the left side at the brake mounts, and will provide power-out via a chainring mounted to the right side spoke flange. This chainring will pull a chain that drives a single cog on the rear wheel.

Hard to picture, so I'll get pix ASAP.
 
OK, some pictures:

This one is hard to follow, but it's a pic of an overhead view of the design. Pedal cranks are at the top of the pic, NuVinci-as-jackshaft at the bottom.
DSCF4146.JPG


Steve and I are building a wooden frame/mockup of the system to get everything in order. Note to self: Why am I using plywood when maybe plexiglass/see-through plastic would be better for visualizing everything?
Here's a pic of the initial "box"
DSCF4156.JPG


Notice the T-Slots extrusions at the bottom. The common power module (CPM) will have two separate sections with different widths. The foremost part will be narrow, basically a width friendly to the bottom bracket width. Farther back, the box will have to be wider to accommodate the 135mm OLD of the NuVinci. Chain lines and heel strike will determine the specific placement of everything. But for now the way we have the T-Slots set up allows for flexibility of these two parts.
DSCF4159.JPG


Motor power will be applied to the NuVinci on its left side - meaning of course there will be no "through the gears" mechanical advantage for the motor. Gears are for the human only. For more info about how this will work, see my NuVinci Left Side Freewheel thread.
DSCF4157.JPG


The rear triangle will be full suspension, with suspension pivot concentric to the NuVinci. Power from the NuVinci will come from a chainring bolted to its right spoke flange (not currently installed, but machined and fit tested).

Next steps:
1. Continue building this fit-test box, by installing the bottom bracket, spindle and cranks.
2. Start installing chains to verify chain lines.
3. Build a prototype left-side freewheel, and install it on my folding bike. This way we'll be able to torture test it on the road before getting too tied to it as a component. Might as well prove whether or not the CSK-40 sprag clutch can take the power of an Astro 3220!
 
Best of luck in pursuit of the Holy Grail, you have a challenge for sure, subscribed.

If you could find a way to combine human and motor power to the Nuvinci it would rock.

A few photos of the best gearbox in frame ideas I have seen through many hours of trolling the web, researching a similar line of thought.

It is not easy to incorporate a gear in the frame, I have yet to see one motorized nicely as well.

I won't re-post photos of the Milyard bike which is probably the best of the bunch, it just needs a motor!

priority-cycles-dh-racer (1).jpg

2007-Versus-Gearbox-bike.jpg

upload2.jpg
 
comradegerry said:
Best of luck in pursuit of the Holy Grail, you have a challenge for sure, subscribed.
Thanks very much!

comradegerry said:
If you could find a way to combine human and motor power to the Nuvinci it would rock.
Part of me wants to do that, but my experience with my frist two bikes keeps bringing me back. Going through the NuVinci would be gentler on the motor and controller on steep hills, and would give me a faster top end in flat terrain. But I'm so very satisfied with the power band I have now, it would be hard to justify. Conversely, there will be so very few parts shared by the power sources - a couple chainrings and a chain - so in the event of a systems failure, I'm all but guaranteed to have a "pedal home" mode.

But you're right. Perhaps when this project is up and running on the road, my drive to continually improve things will compel me to take on that challenge.

comradegerry said:
A few photos of the best gearbox in frame ideas I have seen through many hours of trolling the web, researching a similar line of thought.
To me the ultimate in drive systems is the electric "Pinion" system: http://www.electricbike.com/pinion/
But, where can one be found? And what are its limits - can I volt up the motor and put 750 watts through it? Bah! I'm tired of waiting for an off the shelf solution. Too many market forces and regulations to allow a company to produce what I really want.

The quest continues...
 
If you are not going to run the motor through the nuvinci, what is the reason for using it as a jackshaft and not as a hub? Seams like extra complexity for no gain.
 
drewjet said:
If you are not going to run the motor through the nuvinci, what is the reason for using it as a jackshaft and not as a hub? Seams like extra complexity for no gain.
Great question.
The reasons I cite in the first post, even when coupled with the constraints and goals of my next build, are credible but perhaps not compelling. Here's a little more of why I've chosen this path.

1. I enjoy the hobby aspect of e-biking, as well as the riding, and I'm learning a heck of a lot with this project. So, the complexity inherent in this design is a good thing - a challenge to overcome, requiring me to learn new tools and techniques.
2. I'm paying up front with cost and complexity, hoping that down stream there will be rewards. I e-bike year round, in all weather. This past winter I had several days where slush and gunk caked onto the wheels, and even washing the bike down was not adequate (the slush from the morning commute already started to corrode the rim a bit). Make the wheels somewhat sacrificial is the theme here - but also enjoy lower unsprung weight, and easier wheel swap (slicks for knobbies, etc).
3. Finally there's the anti-reason: what, if anything, is the problem with running the drive through the NuVinci? I've taken a NuVinci N-360 freewheel apart (see the last 10% of this web page for some pix on how). It just does not look like it's robust enough to handle human power + 4 to 5 KW bursts of power. And if the freehub fails, I'd lose both e-power and human power. If there's anything I want from a go-everywhwere, do-everything commuter/grocery getter bike, it's a limp-home mode using either e-power or human power alone.
 
MattyCiii said:
1. I enjoy the hobby aspect of e-biking, as well as the riding, and I'm learning a heck of a lot with this project. So, the complexity inherent in this design is a good thing - a challenge to overcome, requiring me to learn new tools and techniques.



Now there is a great reason. I have done many things in this world just to either learn it, or so I can say I did it.

MattyCiii said:
2. I'm paying up front with cost and complexity, hoping that down stream there will be rewards. I e-bike year round, in all weather. This past winter I had several days where slush and gunk caked onto the wheels, and even washing the bike down was not adequate (the slush from the morning commute already started to corrode the rim a bit). Make the wheels somewhat sacrificial is the theme here - but also enjoy lower unsprung weight, and easier wheel swap (slicks for knobbies, etc).



On my mountain bike I have the dual rear freewheel that was broached by LFP and his dad. I have an original recumpence reduction drive and I love the setup. I use a standard rear wheel, but do use a rear derailerler as I kept the front 3 chainrings. I do like the simplicity of that over having a nuvinci hub.

MattyCiii said:
3. Finally there's the anti-reason: what, if anything, is the problem with running the drive through the NuVinci? I've taken a NuVinci N-360 freewheel apart (see the last 10% of this web page for some pix on how). It just does not look like it's robust enough to handle human power + 4 to 5 KW bursts of power. And if the freehub fails, I'd lose both e-power and human power. If there's anything I want from a go-everywhwere, do-everything commuter/grocery getter bike, it's a limp-home mode using either e-power or human power alone.

I only ever played with the developer Nuvinci, and while it was uber cool, I did not like the weight of it, and it did not like the 10,000 watts I shoved down its throat.

Good luck on your project, I will be following with keen interest. I have a CSK40 sitting on my desk waiting for me to dream up what I will do with it. I am currios to see how yours holds up.
 
nice project...still, the point is to use a motor with thin laminations and low idle current and combine it with human power :?

this would be a real hybrid, since it uses the synergies of both powers. A Alfine-8 can stand a lot if geared for high rpm. You just need a lot overdrive to the gearhub. Like 44/14 like I do with my converted Hubs ;)

NuVinci eats to much power... it can't las a few KW, since it turns ONE into heat..that ONE kilowatt wont stay inside ;)

A gearhub placed in the frame has always the great advantage of a very light rear wheel, which can be replaced by nothing :shock: I use both heavy direct drive and middrive, the middrive feels so much lighter and better in rough terrain :? I use 34-13T cassette. I still would no want to change that for a gearhub-in-the-frame, because it is so simple and works great. It's so lightweight and efficient and simple to maintenance. The only thing I see I would swap it for would be a phaser gearbox with massive power http://endless-sphere.com/forums/viewtopic.php?f=28&t=45392#p661822
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THANKS Crossbreak. You are a true innovator on this forum, and have a lot of great ideas and approaches to share.
crossbreak said:
nice project...still, the point is to use a motor with thin laminations and low idle current and combine it with human power :?
I'm using Astroflight motors, not sure how thin the laminations are but the motors overall are supposedly top notch.

crossbreak said:
NuVinci eats to much power... it can't las a few KW, since it turns ONE into heat..that ONE kilowatt wont stay inside ;)
This puts into words something I had not thought consciously answering Drewjet and Comradegerry. Why don't I want to run e-power through the NuVinci and take advantage of the gearing? Add "the NuVinci is too inefficient" to my answers. But for pedaling... I'm willing to sacrifice some inefficiency for the awesome feel of index-free shifting.

crossbreak said:
A gearhub placed in the frame has always the great advantage of a very light rear wheel, which can be replaced by nothing :shock: I use both heavy direct drive and middrive, the middrive feels so much lighter and better in rough terrain :? I use 34-13T cassette. I still would no want to change that for a gearhub-in-the-frame, because it is so simple and works great. It's so lightweight and efficient and simple to maintenance. The only thing I see I would swap it for would be a phaser gearbox with massive power

Hopefully once fully designed, this project will be easy to implement: just a couple of parallel aluminum plates with precision cut holes for spacers, motor, and NuVinci jackshaft (this is a bit of simplification). The NuVinci is expansive, and heavy - I will certainly be open to other options in future iterations - but for its heft and price, it is a single component, proven to be robust, but in the event of failure easy to swap out.
 
the Nuvinci isn't that expensive. There are version made for higher power levels/rpm like the NuVinci Delta series which might be more suitable for a hybrid drive. Astro motors are perfect for this application :)


BTW, I developed a new fastening method for Jackshafts in general. It utilizes a chain tensioner function by varying shaft distance: http://endless-sphere.com/forums/viewtopic.php?f=28&t=45245&start=525#p747479

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Hi Matty

Pinion have taken all reference to E1.8 of of their website from what I can see, it did look perfect though which is a tragedy.

Last year when I inquired after it, I received the reply below from the sales manager.

"thanks for your interest in our Pinion E1.8. Currently this gearbox with e-motor support is still under development and not available yet. So we cannot comment on technical details at this stage. We hope to be able to show a first prototype on the 2013 Eurobike show. Serial production definitely won’t run before 2014.

One of our customers, a Swiss company named http://www.protobike.ch/ already successfully combines our Pinion P1.18 mechanical gearbox with a rear hub e-motor in their special cruiser bikes. Maybe this could also be solution for your plans?
With kind regards,
Philip Plagens"


I was also told by the good people that make the G-Boxx that they are no longer making them anymore, so Ebikes with a gear in the frame seem to be restricted to modding an IGH or something like Thuds 2 speed box at the moment.....

With a decent motor 3 speed box is all that would be really required I reckon for most folks.
 
comradegerry said:
...


I was also told by the good people that make the G-Boxx that they are no longer making them anymore, so Ebikes with a gear in the frame seem to be restricted to modding an IGH or something like Thuds 2 speed box at the moment.....

With a decent motor 3 speed box is all that would be really required I reckon for most folks.

There is still the option to use the 50cc gearboxes: http://honda50.com/speedcalc/speedcalculator.html like silvio did: http://endless-sphere.com/forums/viewtopic.php?f=28&t=42262#p618667

12%2520-%25202.jpg
 
I am really looking forward to what you come up with. See how the professionals handle it.

I did a lot of work towards creating a nuvinci and hub motor removable drivetrain component which I could easily move from my trike to a future bike. So...I think you have a great idea. However, I decided against it. I may do something like this someday, but I decided instead to keep the nuvinci permanently attached to the trike, and just have the motor, controller, and batteries be easily removable. This allows me to keep regen. It also allows me to ride the trike with only pedal power. The two shift patterns on the nuvinci are perfect...one with motor...one without. I can put on an economy motor or a speed motor. It was just better for me.
 
comradegerry said:
Hi Matty

Pinion have taken all reference to E1.8 of of their website from what I can see, it did look perfect though which is a tragedy.

Last year when I inquired after it, I received the reply below from the sales manager.

Pinion said:
"thanks for your interest in our Pinion E1.8. Currently this gearbox with e-motor support is still under development and not available yet. So we cannot comment on technical details at this stage. We hope to be able to show a first prototype on the 2013 Eurobike show. Serial production definitely won’t run before 2014.

One of our customers, a Swiss company named http://www.protobike.ch/ already successfully combines our Pinion P1.18 mechanical gearbox with a rear hub e-motor in their special cruiser bikes. Maybe this could also be solution for your plans?
With kind regards,
Philip Plagens"


I was also told by the good people that make the G-Boxx that they are no longer making them anymore, so Ebikes with a gear in the frame seem to be restricted to modding an IGH or something like Thuds 2 speed box at the moment.....

With a decent motor 3 speed box is all that would be really required I reckon for most folks.
Wow that's great information to share. Frankly if Pinion's message was "The Pinion E1.8 can handle up to 3KW input, and is available as of May 2013 for $2500 - drive only, BYO bike", I'd abandon this thread right now and bust out my credit card.

But alas, no.
 
crossbreak said:
There is still the option to use the 50cc gearboxes: http://honda50.com/speedcalc/speedcalculator.html like silvio did: http://endless-sphere.com/forums/viewtopic.php?f=28&t=42262#p618667
THANKS for the reminder! I subscribed to that thread but somehow lost track of it (too. many. subscriptions!) I will reread it... it looks like the 50cc gearbox might be something worthwhile to integrate into the plan.
 
Sancho's Horse said:
...I did a lot of work towards creating a nuvinci and hub motor removable drivetrain component which I could easily move from my trike to a future bike...
Good stuff!
Modular is the name of the game here. I guess 'modularity' can be applied in different ways. My application is - Common Power Module is easy to build, and so several are built. But from that center, it's adaptable/suitable to the end user building up a longtail cargo bike, a full suspension bike, a folding bike, "Bakfiets" style cargo bike, or other around that same center. So... not as much about reusability as it is about what different things can be built up from the common core.

But on the topic of reusable components... I hope to evolve the battery box from my A-Line into something quite modular. Suppose I had two pelican cases, with the same VESA mount adapter. One is on the charger at home while the other is on the bike when I ride. A 5 minute pit stop at home, I swap them out... drained batteries are now charging, fresh ones on the bike. And perhaps if all my bikes use the same VESA mount to hold the battery box... well, battery reuse will be a big cost savings!
 
I built 7 ebikes and 4 Lipo batteries with BMS yet. I can all use with all, since they all use the same XT60 plugs. Batteries are expensive. All of my drives are in the 100-200€ region :p except my HS3540 which was a bit more expensive.

But pack to topic: The GNG-Drive fits almost any bike, since it uses the BB to fasten it. BB are almost all the same, 68-74mm wide. This mount can be really stiff also. Already posted my new BB mount above. A 5-speed 50cc gearbox with a sprocket for the pedal drive would be one option. Another would be to integrate the BB into the CPM and use a full enclosure. Hope I can come up with some CAD pics as soon as I have time for that. Many good ideas here, keep it going!
 
crossbreak said:
Another would be to integrate the BB into the CPM and use a full enclosure.
That is absolutely the plan.

Here's an early concept drawing of my 3rd bike project, the CPM being the big funny looking square-ish mass under the seat, aft of the top tube, and attached to the swing arm & shock.
DSCF4180.JPG
 
Hi Matty

Check this out for inspiration.... All it needs is a little electrical motivation to be sweet.

The article shows the gearbox in some detail.

Best of luck with the build.

http://www.pinkbike.com/news/Roc-DAzur-2012-Cavalerie-DH-Gearbox-Bike.html

p5pb8776174.jpg
 
The effigear is much like the Pinion. Sadly you can order that one nowhere. If one could order, it would be in the $2000+ price range :? Thinking more towards a 5-speed 50cc gearbox.

Notice how nice the space of the frame width is used by the gears. If one would attach this to the BB and have the gears in front of it, this could be a quite compact gearbox. Still, somehow the pedal must get connected. I like using a gear drive to make the turning direction work the right way. Even if this gear transmission from pedals to the first shifter axle would be attached on the outside of the CPM. Silvio did this with the motor reduction in his gearbox, to save some width for the long motor:

remdering%252011.JPG
 
MattyCiii said:
crossbreak said:
Another would be to integrate the BB into the CPM and use a full enclosure.
That is absolutely the plan.

The position of the pedal change then :( this leads to a lot of problems. For example, if you put the pedal axle in front of the BB, you might touch the front wheel with your feet while pedaling
 
Just to get an impression of the sizes and distances.


Crank-> shifter-shaft 70T/12T module 2
chain to wheel: 20T

4-speed gearbox is the same that silvio uses, guess they are module 2:
I 10/33 => 25 km/h
II 15/29 => 42 km/h
III 19/24 => 65 km/h
IV 21/22 => 78 km/h
 

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