2, 3, or more speed direct drive hub motor

wesnewell

wesnewell

100 GW
Joined
Jan 31, 2011
Messages
7,171
Location
Wylie, TX, USA
Anyone make a multi-speed automatic DD hub motor? One that would start out with lots of torque, and then start changing winding taps as the speed increases. This seems like something that would simple to do a couple of different ways, but I haven't seen one. Anyone?
 
Crystalyte did. But it didn't change the actual torque, just the efficancyat lower speeds.

I have one, its brilliant. but of limited use. Its a 408/4012 combo. the original controller had a switch to flip between the windings. With my riding style, I get around 23W/mi on the 4012, and yesterday I was getting 29W/mi on the same route using the 408 exclusivly. I ride about the same speed regardless.
 
What would be the effect if a hub motor was built to allow a rolloff in the center?
 
I was thinking you'd have to get more torque using all the winding as it would create a stronger field. And isn't that the reason they make motors with different windings to begin with? I pretty sure it is although I haven't built a motor since shop class 50 year ago. I guess flipping a switch would be ok, but I was thinking more along the lines of a centrifugal switch inside the motor housing to do it automatically with an adjustable tension spring. And maybe a 15 turn winding with taps at 5, 10, and 15.
 
A 2 or 3 speed geared hub with a strong transmission and gears designed for small motorcycle use is exactly what we need. The Chinese don't appreciate the need, the Japanese are stuck on low power, and the Germans think their ebike innovations are worth more than an entire new car, so who's going to do it? Due to weight, the solution is more likely to come as a unit driven by chain or belt outside of the wheel, and we're starting to see those types of drives, just too low power and too expensive for me.
 
wesnewell said:
I was thinking you'd have to get more torque using all the winding as it would create a stronger field. And isn't that the reason they make motors with different windings to begin with? I pretty sure it is although I haven't built a motor since shop class 50 year ago. I guess flipping a switch would be ok, but I was thinking more along the lines of a centrifugal switch inside the motor housing to do it automatically with an adjustable tension spring. And maybe a 15 turn winding with taps at 5, 10, and 15.
Click to expand...

An electrical change is inadequate and already exists, primarily with Delta/Wye switching. I have a 2kw scooter hubmotor like that, which isn't made anymore. A real mechanical gearing change is what's needed.

If giving up the ability to roll backward is acceptable, then a retro-direct 2 speed in a geared hub would be pretty simple and could be done with a weight less that the DD hubbies. 2 sets of planetaries with different gearing, 2 oneway bearings, and a motor reversing switch, is all it would take.
 
IIRC someone showed pictures of a 3 speed internal geared Chinese hub motor way back. The pictures were probably lost when the server crashed. I'll see if I can find the reference.
otherDoc
 
Is a hub still direct drive if it has gears?

solarbbq was talking about one http://endless-sphere.com/forums/viewtopic.php?f=2&t=9043
More of a scooter motor than a bicycle.

file.php
 
I would like to see the Delta/Wye run by FETs inside the hub with the right mechanical cooling but the main part of the controller outside the hub with the exception of the electronics to do the switching. I think that when the blue tooth signalling is possible that this will be done.
 
More of a scooter motor than a bicycle.
Click to expand...
Or, a bicycle motor for hot-rodders like LFP!

Two or three gears is a great thing. There is a growing number of E-bikers who are expressing satisfaction with the performance of Bottom-Bracket (BB) drives, like Cyclone or Elation. Cyclone suffers from some weak components that need to be upgraded soon. I believe Miles has a SRAM Dual-Drive with two independent freewheels to the rear wheel. One for pedaling, and one for the motor only, which gives the motor 3 gears.

I am certain that a planetary set can be configured to create a 2-speed transmission (its been done before, see Schlumpf http://www.utahtrikes.com/ARTICLE-33.html), but there is nobody doing this with a hub-motor (yet), and such a 2-speed trans could easily be packaged inside the existing housing of a common 9C hub.

There is a dozen ways to add gears to the motor for a non-hub, such as using a 3-speed hub for a jackshaft (like the Sturmey-Archer, Nexus, etc) I have seen both gasser bicycles and electric that have done this. There is nothing for sale right now like this, so it involves custom brackets and custom sprocket/pulley adapters...
 
Bionx had made 3 speed internal with SRAM component in it combine with their hub motor into one unit:
http://www.bionx.ca/en/about-us/news-and-events/?id=4BionX_IGH3.jpg
They actually had made 7 speed internal, for whatever reason during the production, they only made 3 speed.

Ken
 
itselectric said:
Bionx had made 3 speed internal with SRAM component in it combine with their hub motor into one unit:.

Ken
Click to expand...

Though thats a 3 speed for the chain drive portion. the Hub motor is still a fixed 1:1 as will all direct drive motors, as i understand it. The motor doesn't change gears, the rider does.
 
I was thinking if you had a mechanism to lock and unlock the planetary gears in a geared hub motor you could have a 2 speed. It is hard to conceptualize but it seems that it would work. First gear you are driving the planetary gears second gear it is direct drive. I'm not sure if you would need to reverse the motor to make second gear turn the wheel in the correct direction but that could be accomplished if needed.
Another thought is that the stator of a crystallite is so huge that it could contain a three speed hub. How the three speed hub would connect to the various parts of the crystallite is also difficult to imagine but possible in a world of unlimited money and machine shop time.
The bion x seems dumb since it only changes the gears for the pedals. If you want a hub motor and an internal shifting hub it is easy enough to put the hub motor on the front wheel.
 
mr.electric said:
I'm not sure if you would need to reverse the motor to make second gear turn the wheel in the correct direction but that could be accomplished if needed.
Click to expand...
Reversing the motor would be the simplest way to make the gear change.... :wink:
 
I wonder if a schlumpf crank could be combined with a crystallite to accomplish the 2 speed hum motor. The spindle of the schlumpf would become the axle and be fixed to the drop outs. The chain ring of the schlumpf would become the right side cover of the crystallite hub.
 
You could just do a dualie - high speed wind on the front - high torque wind on the back - Instead of a $500 x5 - you could get away 2 $150 9c and two smaller controllers rather than one giant 18fet.
At least that's what I'm planning on doing for my next build.... the price is about the same... honestly I'm surprised no one has tried it yet.

Another thing to think about - how would the controller handle the sudden change in RPM from shifting gears?
I'm really excited about the future of multi-geared hub motors. On any vehicle they make just about everything super simple. Imagine a 4 wheeler with hub motors. The thing would have low center of gravity, tons of ground clearance, and the ultimate traction control.
 
auraslip said:
You could just do a dualie - high speed wind on the front - high torque wind on the back - Instead of a $500 x5 - you could get away 2 $150 9c and two smaller controllers rather than one giant 18fet.
At least that's what I'm planning on doing for my next build.... the price is about the same... honestly I'm surprised no one has tried it yet.

Another thing to think about - how would the controller handle the sudden change in RPM from shifting gears?
I'm really excited about the future of multi-geared hub motors. On any vehicle they make just about everything super simple. Imagine a 4 wheeler with hub motors. The thing would have low center of gravity, tons of ground clearance, and the ultimate traction control.
Click to expand...
I was thinking of almost the same except a BMC highspeed in the rear and torque in the front!
 
Nothing replaces good old gear ratios. What about a 29" wheel in front and a 20" in the back both with identical motors. Rear motor is first gear front is second.
 
IIRC Schlumpf and two other companies make a planetary 2-speed to replace the BB. It provides a smaller "chainring" of sorts to make MTBs have better rock-crawling clearance. There are (of course) 3 elements to a planetary set: sun, ring, and planets. Schlumpf and their 2 competitors use a small axial dog-clutch (operated by a side-to-side rod inside a hollow BB-axle) to lock the ones that makes the turning directions the same for both (I believe its DD for first, and overdrive for second).

The Ford Model-T had a planetary transmission. Two forward speeds and a band-lock to actuate a reverse. Simple, rugged, and inexpensive. There is room inside a 9C to have a Schlumpf, but it would be a nightmare to adapt (and expensive at Schlumpf prices). Designed from the ground up in China, it would be an upscale game-changer. Especially if they had a scooter or motorcycle-sized unit, as they need the battery-efficiency range even more than bicycles.

I am thinking about experimenting with a cell_man geared hub. I think the gears run at about a 5:1 ratio, so removing the gears and using a chain/belt to the rear wheel, I want it to drive a 3-speed rear-wheel (perhaps a Nexus-3). Without the plastic planets, it will be a DD-outrunner about 5" in diameter with no gear-whine. Without the shell, it will run cooler than in the standard geared-hub configuration. More study needed, wish me luck...
 
There is no such thing as a high torque motor or a high torque wind. It only spreads confusion by repeating this drivel.
Click to expand...

No sarcasm on my part, but thank you. I know little to nothing about motors, winds, and the physics behind them. Perhaps, phrased differently I could say a motor wound to produce lots of power in the low end paired with a motor with a higher Kv for the front?
 
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