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5 hours ago, 陈小杰 said:

I designed a motor that has been patented in China, which will change the design of EUC.

 

0170617113422.jpg

 

4 hours ago, lizardmech said:

Someone did this already.

095346tqtgs7fg1wsk5ajj.jpg

These, pedals mounted directly on motor or not, are the way to go in the future. No more flimsy 14-18mm axles just waiting to break. If you mount the pedals directly on the motor, I would suggest that the connection is made really heavy duty, since it can't be replaced easily.

I would like to see these ideas translated into a commercial wheel: With an 16-18" diameter 2.5" with tyre; with a 2000W nominal motor with plenty of torque.

Mounting the controller in the hub is an interesting concept, but more important is to have a controller that can take the abuse we place on them and have adequate cooling. 247s are brilliant, but use 12 of them not 6, make sure all other components have a serious margin too before burning out. And all cables should be heavy duty and all connectors should be able to take both high temperatures and vibrations.

@陈小杰 I have to applaud you for thinking outside the box, but don't get into unnecessary patent fights. The wheel @lizardmech showed you is like yours in concept, but we need both. We need someone or someones that dare point the way past the current limitations.

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On 6/5/2017 at 5:04 AM, 陈小杰 said:

92.4V  944WH  88PCS 18650

Maximum speed 70KM
Has been tested for three months
 
 

IMG_4692.JPG

I want one!

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Posted (edited)
On 2017-6-17 at 11:25 AM, Scatcat said:

No more flimsy 14-18mm axles just waiting to break.

There is no reason that an axle cannot be larger than 18mm and there is also no good reason that an 18mm must break, other than lazy or careless engineering, IMHO.

I believe the design with the hole in the middle makes the choice of bearings more difficult, at least in practice. Bearings are the only part of an EUC which needs to move (smoothly) under full weight load. With the hole in the middle, the bearing becomes much larger and (much?) heavier and the bearing seal needs to cover a much larger area with higher speeds against each other. This engineering problem might have a reliable solution, but it will not come from engineers who cannot even design a reliable axle.

Edited by Mono
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19 minutes ago, Mono said:

There is no reason that an axle cannot be larger than 18mm and there is also no good reason that an 18mm must break, other than lazy or careless engineering, IMHO.

I believe the design with the hole in the middle makes the choice of bearings more difficult, at least in practice. Bearings are the only part of an EUC which needs to move (smoothly) under full weight load. With the hole in the middle, the bearing becomes much larger and (much?) heavier and the bearing seal needs to cover a much larger area with higher speeds against each other. This engineering problem might have a reliable solution, but it will not come from engineers who cannot even design a reliable axle.

I think you overestimate the problem.

  • We use axles bigger than this on both lorrys and trains, aircraft and ships where the stresses are at least as high and there needs to be a tight seal. It may be more expensive, yes, but it requires no new technology per se.
  • The weight difference will probably be slight compared to the weight of the wheel as is.
  • The stresses involved will actually be smaller, since the weights involved will be spread over a larger amount of gearing components (balls, rolls, races, cage).
  • Also the technical difficulties depends to a large degree on how big you go. If you go hand-span size as in the pictures, the engineering problems are less than if you go full "orbit".

I'm not saying there will be no problems, but compared to the problems we already have with not fully trusting our axles... I think it's worthwhile.

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Posted (edited)
2 hours ago, Scatcat said:

I think you overestimate the problem.

  • We use axles bigger than this on both lorrys and trains, aircraft and ships where the stresses are at least as high and there needs to be a tight seal. It may be more expensive, yes, but it requires no new technology per se.
  • The weight difference will probably be slight compared to the weight of the wheel as is.
  • The stresses involved will actually be smaller, since the weights involved will be spread over a larger amount of gearing components (balls, rolls, races, cage).
  • Also the technical difficulties depends to a large degree on how big you go. If you go hand-span size as in the pictures, the engineering problems are less than if you go full "orbit".

I'm not saying there will be no problems, but compared to the problems we already have with not fully trusting our axles... I think it's worthwhile.

It seems you make an equivocation of the word problem using it with two different meanings in the last sentence. The first refers to the challenge ("problem") of engineering a reliable product and the second to failures ("problems") we have observed in existing products. These are different things. We can observe many failures of a product which poses very little engineering challenge, for example due to a mistaken specification.

You really disagree that it is a much much much simpler to replace a weak axles with a more sturdy one than to have an entirely new motor design with a much larger hole in the middle? Strange.

Edited by Mono

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1 hour ago, KingSong69 said:

perhaps my view is a bit overdrawn....but who ever experienced a cutout, fall, crash which is related to technics...looses a lot of trust in our beloved gadgets and keeps wishing for a much more intense view on safety!

Not overdrawn one bit! I believe the firmware, control boards and wiring are the main safety issues at the moment. I'm kind of glad my ACM mods are not completely finished given the recent issues with the MSuper and ACM! I hope there are some definitive answers from GW soon concerning all of the unsolved dangerous cutouts!

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2 hours ago, KingSong69 said:

perhaps my view is a bit overdrawn....but who ever experienced a cutout, fall, crash which is related to technics...looses a lot of trust in our beloved gadgets and keeps wishing for a much more intense view on safety!

Yep, better mechanical design is certainly a great step forward. But primarily we need much improved and redundant electrical designs!

But I guess mechanical is cheaper and easier to do and a more visible change, so manufacturers start with that.

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4 hours ago, Mono said:

There is no reason that an axle cannot be larger than 18mm and there is also no good reason that an 18mm must break, other than lazy or careless engineering, IMHO.

In my profession throughout the design phase, prior to fabricating an orthopedic brace, there are a number of considerations taken into account so the device ends up being biomechanically sound.  Activity level and weight are always key factors. When I fabricate the appliance it has been designed to exceed all tolerance levels. I had one child fall and break a leg during my career due to a maladroit design flaw. Once was enough. Now all of my orthopedic appliances are over engineered!

It would be nice if EUC manufacturers would follow a similar paradigm before more riders become injured due to attenuated components that are underengineered!

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1 hour ago, Mono said:

It seems you make an equivocation of the word problem using it with two different meanings in the last sentence. The first refers to the challenge ("problem") of engineering a reliable product and the second to failures ("problems") we have observed in existing products. These are different things. We can observe many failures of a product which poses very little engineering challenge, for example due to a mistaken specification.

You really disagree that it is a much much much simpler to replace a weak axles with a more sturdy one than to have an entirely new motor design with a much larger hole in the middle? Strange.

From time to time, the fact that English is my second language shines through a little bit. Yes indeed I used "problem" with two different meanings. But I should have been clearer and used challenge in the first sentence. 

Yes I think the comparison of the challenges making such a change are small, compared to the problems it would solve.

No I don't think it would be useless to simply replace the axle with a sturdier one with slightly larger diameter and better materials.

But when I see bright ideas, I want to promote them.

And yes I fully concur that electrical redundance, good components, and good firmware are even more important.

I seriously hope one doesn't preclude the other. 

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The issues we see right now are:

- axle is designed for bicycle application were the force is applied perpendicular to the axles with no torsion arm. In that application it functions with no issues. The EUC Has a torsión arm applied to the axles to hold a pedal. That it's why it breaks. Also the axle is cut like 50% to make treads. And then cut further to create a flat square surface to prevent rotation. Then cut further by hollowing axle for the cables.  A simple solution is to not cut down the circumference and keep the original with. Also do not cut square face. A set-screws is suficient.  Possibly two set screws. 

-next is the MOSFET issue there is no reason for burning them. They need to figure out why. One is soldering is damaging component or they are buying black market components or ESD damage, or circuit design allows damage. 

-next is BMS over current cutoff software could prevent that by warnings and limiting. No reason to cutoff power. Power cutoff should only be used for a system failure. 

 Just these three issues would eliminate 95% of the current problems and none require any re-engineering. 

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Just because I'm curious Chen Xiaojie/@陈小杰, what's your role in the company? Are you one of the innovators?

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53 minutes ago, 陈小杰 said:

https://www.youtube.com/watch?v=YhJNr67qmyc 

The people who ride are me, but you will not think of who the photographer is.

A fellow rider ;), that is awesome.

So @陈小杰, I know we can sound very negative from time to time, but I truly appreciate both you being here to talk with us, and your responses.

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1 hour ago, 陈小杰 said:

@Scatcat  yes I am in a number of positions.

Could you make a new GR16 model with metal helical gears instead of the nylon straight cut? I think people would be willing to pay a little more to cover the cost of the gears.

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@lizardmech I have never used nylon gear, GR series are metal gears,I like gear motors, but now there is no money to optimize the process.

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1 hour ago, 陈小杰 said:

@lizardmech I have never used nylon gear, GR series are metal gears,I like gear motors, but now there is no money to optimize the process.

Oh I didn't know gr16 was metal gears inside, I had only seen ebike with similar motor. What trouble did you have with gear motors that needs more money for development?

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1 hour ago, Hunka Hunka Burning Love said:

It would be cool to see a CVT system like this in a EUC, but I think it would be too complicated and expensive to incorporate.  They do seem to have them in bicycles.

http://www.fallbrooktech.com/nuvinci-technology

 

This might be an alternative for geared EUC, I can never find any chinese companies making them on alibaba though.

 

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Posted (edited)
20 hours ago, lizardmech said:

Oh I didn't know gr16 was metal gears inside, I had only seen ebike with similar motor. What trouble did you have with gear motors that needs more money for development?

I think they ultimately were unreliable over time with wear of the components most likely even though they packed them with grease.  Also they were noisy as heck.  I remember seeing a video and photos of one opened up.  It was quite the set up with a bunch of orbital gears inside.

 

Edited by Hunka Hunka Burning Love

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